Presidential candidate Bernie Sanders released his tax returns from the past 10 years on tax day, April 15, revealing that in recent years he has entered the class of millionaires he so often critiques.

Since launching his first presidential campaign in 2015, the Vermont independent has gained newfound financial success.

Sanders and his wife, Jane O’Meara Sanders, have reported more than $2.7 million in income since 2016, most of which was earned from the senator’s bestselling book "Our Revolution."

When it was published in 2016, Sanders earned $840,000 in profits, the filing shows, but the couple’s earnings peaked the following year, when they reported income of $1,131,925.

Sanders is one among several Democratic presidential candidates who have been publicly disclosing their finances, part of an effort to contrast themselves against President Donald Trump, who broke with longstanding tradition in 2016 when he refused to release his returns.

During his first presidential bid, Sanders was also reluctant to make his financial information public, releasing only his 2014 tax return.

Before 2016, Sanders frequently pointed out that he was "one of the poorest members" of Congress. This became a common refrain while he was on the campaign trail running against former Secretary of State Hillary Clinton. At the time, he ranked in the bottom one-fifth of senators for net worth.

A vocal critic of income inequality, he also railed against the wealthiest "1 percent" of Americans and their stranglehold on the political system. Now he finds himself entering their ranks.

In a statement, Sanders said that his tax returns show his family has been "fortunate" in recent years. But he maintains that his wealth has not changed his stance that richer Americans should shoulder more of the tax burden.

"I consider paying more in taxes as my income rose to be both an obligation and an investment in our country," Sanders said. "I will continue to fight to make our tax system more progressive so that our country has the resources to guarantee the American Dream to all people."

In 2016, the first year Sanders and his wife’s earnings topped $1 million, they paid the federal government $396,507 in income taxes. This included $24,000 the couple overpaid, and for which they did not request a refund, according to tax returns.

That same year the Sanders family purchased a lake house in North Hero for $575,000. Sanders paid for the home without taking out a mortgage. At the time Jane Sanders said they used profits from the sale of her share of a family property in Maine to purchase the summer home.

Sanders’ earlier tax returns, dating back to 2009, show much smaller earnings. The couple’s adjusted gross income hovered between $200,000 and $325,00. During this time, Sanders main source of income was his $174,000 Senate salary.

The Sanders’ annual income reached its highest point in 2017 when they earned $1,131,925. The bulk of the money came from book sales. That year the couple paid about $340,000 in taxes.

In 2018, his income dipped to $561,293, according to tax returns.

Democratic candidates have placed new emphasis on financial transparency in the 2020 election cycle. The Sanders campaign promised early in his candidacythis cycle that he would release his financial records.

On April 14, Sen. Kamala Harris, D-Calif., released 15 years of tax returns, showing that she and her husband made a total $2 million in 2018.

Sens. Kirsten Gillibrand, D-N.Y., Elizabeth Warren, D-Mass., and Amy Klobuchar, D-Minn., have all released their returns. Sen. Cory Booker, D-N.J., and Beto O’Rourke of Texas and South Bend Mayor Pete Buttigieg say they will soon follow suit.