By 1989, the top 20 per cent owned 83 per cent of the country's wealth, while the bottom 80 per cent owned 17 per cent.
That same year, the top 1 per cent owned 35.2 per cent of the country's wealth. By the late 1990s, the top 1 per cent owned 38.1 per cent.
In 2001, the top 20 per cent held 84.4 per cent of all wealth; the bottom 80 per cent held 15.6 per cent.
But that same year, the top 1 per cent's share of overall wealth fell to 33.4 per cent.
Since 2001, the top 1 per cent have steadily gained more and more of the country's wealth.
In 2004, it held 34.3 per cent; in 2007, it had 34.6 per cent; in 2010, its share rose slightly to 35.1; in 2013, the share was 36.7.
In 2016, the richest 1 per cent owned nearly 40 per cent of this country's wealth.
The top 20 per cent owns 90 per cent of the country's wealth, while the bottom 80 per cent owns just 10 per cent of all income and net worth.
In October, Forbes released The Forbes 400 list of richest Americans. Leading the way was Microsoft co-founder Bill Gates ($1.3 trillion), followed by Amazon founder Jeff Bezos ($1.19 billion), Warren Buffett ($1.14b), Mark Zuckerberg ($1.04b) and Larry Ellison ($86b) rounding out the top five.
In September, the Federal Reserve released a study saying that while most American families grew richer between 2013 and 2016, the wealthiest households pulled even further ahead, worsening the nation's massive disparities in wealth and income.
The median net worth of all American families rose 16 per cent last year from 2013 to US$97,300 ($142,589), according to a Federal Reserve survey.
The median is the point where half of families fall below and half above.
That's the first gain for middle class households since the recession upended the economy nearly a decade ago.
The figures echo data released earlier in September from the Census Bureau, which also showed middle-class incomes rising.
Since 2015, the economic recovery's benefits have been spread broadly, to nearly all income levels and racial and ethnic groups.
But those gains arrived after the first five years of the recovery, when higher-earning households reaped most of the benefits.
A low and falling unemployment rate has helped push up pay, while rising home prices have restored some wealth to middle income families.