Five fresh facts you might not know about inequality

In the world of luxury boats, one expert observes that "the client who 15 years ago would have been satisfied with a 40-metre yacht, which would then have been one of the largest yachts in the bay, is now surrounded by dozens of yachts of 60 to 70 metres, and this plants the seed that he really ought to upgrade. The world's largest yachts now include multiple swimming pools, submersibles, jet skis, concert halls and dance floors. Running costs alone can be millions of dollars per year. Yet as investment banker Mark Carnegie notes, no matter how large megaboats get, "someone's always got a bigger one".

At the other end of the income spectrum, recreation looks a little different. As one low-income person put it, leisure spending "depends on the situation with bills and gas and electric and so forth". Another said their only leisure is to smoke cigarettes. Recreational activities tend to involve walks and bicycle rides, with one study estimating that for poor Australians, spending $20 a week on recreation was a "generous amount". When his friends go out for a meal to celebrate, one young unemployed man said "it's quite embarrassing - I'll just sit there and not eat".

Plenty of ink has been spilt on the topic of inequality, but research is uncovering new aspects all the time. So here are five fresh facts you might not know about inequality.

First, earnings. The good news is that there's one group in Australia that is enjoying healthy pay increases, with their real remuneration rising four times faster than inflation last year. The bad news? We're talking about CEOs of the largest 100 listed firms, whose average pay is now about $6 million. For the rest of the workforce, things aren't quite so rosy. In recent years, average wages for many workers have grown no faster than inflation. While productivity has grown, the benefits are flowing to firms and their owners, not to employees. Australia has a wage problem.

Second, market concentration is a challenge across the economy. The biggest four firms control more than 80 per cent of the market in sectors as diverse as department stores, health insurance, supermarkets, domestic airlines, internet service providers, baby food and beer. The number of mergers and acquisitions has nearly tripled since 1992. Meanwhile, the rate of new business formation is in decline, leading to an overall decrease in the number of firms in the economy. A recent report from the Productivity Commission found that as a result of the pricing power that major banks enjoy, "approximately half of the average loan price that major banks charge is estimated to be a premium over the marginal cost — double the margin that other Australian-owned banks have and well above that of banks in other high-income countries". A planned takeover of Fairfax by Nine will increase concentration in the media market. Oligopolies are worsening inequality.

Third, Australia has a higher share of the population in jail than at any time since Federation. Fully, 0.22 per cent of adults are behind bars, a rate higher than Britain, Canada and Japan. The incarceration rate has risen despite the fact that many categories of crime have fallen over the past two decades. For example, the murder rate is down by one third, while the car theft rate is down by two thirds. It's true that we have a higher incarceration rate than the United States, which jails 0.86 per cent of adults, but their rate has been falling over the past decade, while ours has been rising. Indigenous Australians are more likely than African Americans to be in jail. This is especially true in Western Australia, where more than 1 in 25 Indigenous adults are currently imprisoned.

Fourth, the rich have seven more teeth than the poor - a gap that shows with every smile. According to surveys that asked people how many teeth they were missing, the affluent were missing an average of three teeth, while low-income Australians are missing an average of 10 teeth. This was brought home vividly to me by the story of Patrick, a Canberra man whose kidney medication all but destroyed his teeth. Patrick grew a 25cm beard to hide his mouth and said his four children were embarrassed about the way he looked. Eventually, Patrick was helped by a pro-bono dental program implemented by the late Liz Dawson, a Salvation Army worker. But thousands of others miss out on care, and the difference in teeth affects people's access to jobs and friends. Some of those who abuse drugs or alcohol say that they started off in order to numb the pain of an aching mouth. The dental inequality gap is just one marker of health inequity. In a study I conducted with Melbourne University's Philip Clarke, we found that the rich live six years longer than the poor.

Fifth, this year's AFR Rich List contains 76 billionaires – 16 more than last year. The total wealth of the top 200 is $283 billion, up 21 per cent since last year. The top handful of billionaires have almost as much wealth as the bottom fifth of the population. Over the past generation, inequality has risen in terms of income and wealth, whether measured by tax data or surveys. But there's nothing inherent in economics that says that the growth must automatically fuel inequity. Indeed, Australia's post-war decades saw solid growth and a marked fall in inequality. From the late-1940s to the early-1980s, the fall in Australian inequality was as large as the inequality gap today between us and egalitarian Scandinavia. We can be a more equal nation if we make smart decisions.

There's no denying that superyachts and supercars are super-beautiful. The question is how much benefit our billionaires get from having a 70-metre boat rather than a 40-metre boat, or a sports car that accelerates from 0 to 100 km/h in four seconds rather than seven seconds. For Australian battlers, the homeownership rate is as low as it's been in six decades, and real wages aren't growing. Unions – traditionally a powerful bulwark against inequality – have a membership rate that's now down to just one in seven workers. The share of national income going to workers is markedly lower than a generation ago. Australia is not on track to meet most of its Indigenous Closing the Gap targets. At the rate the gender pay gap is presently closing, it could take many decades before men and women are paid the same rates.

What could make inequality worse? Reducing the power of unions, making our income tax system less progressive, or pretending that inequality isn't on the rise. What could make Australia more equal? A fairer industrial system, properly funded schools, and a tax system that doesn't leak revenue to the most affluent. That's the choice Australia faces.

Andrew Leigh is the shadow assistant federal treasurer and author of Battlers and Billionaires: The Story of Inequality in Australia.