Bernie Sanders Released His Tax Returns. He’s Part of the 1%.

WASHINGTON — Senator Bernie Sanders of Vermont disclosed 10 years of tax returns on Monday, providing a more detailed look at his finances than he offered when he ran for president in 2016.

The returns show that Mr. Sanders’s earnings shot up after his first presidential bid, when he built up a vast national following. His income topped $1 million in 2016 and 2017, lifted by proceeds from his books.

Mr. Sanders and his wife, Jane O’Meara Sanders, had an adjusted gross income of $561,293 in 2018, according to their most recent tax return. Mr. Sanders had about $393,000 in book income last year, and he and his wife reported giving $18,950 to charity.

Their federal taxes came to $145,840, for an effective federal tax rate of 26 percent.

Mr. Sanders’s higher income in recent years creates some political awkwardness for the senator, who in his 2016 presidential campaign frequently railed against “millionaires and billionaires” and their influence over the political process.

His income now puts him within the top 1 percent of taxpayers, according to data from the Internal Revenue Service.

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“These tax returns show that our family has been fortunate,” Mr. Sanders said in a statement. “I am very grateful for that, as I grew up in a family that lived paycheck to paycheck and I know the stress of economic insecurity.”

The issue of tax returns has been in the spotlight because of President Trump’s refusal to release his own, a position that defies decades of tradition. House Democrats are now demanding to see his returns.

Mr. Sanders’s handling of the issue received attention in the 2016 race, when Hillary Clinton, his main rival for the Democratic nomination, pushed him to divulge years of tax returns, as she had done. At the time, Mr. Sanders said his wife did their taxes. “We’ve been a little bit busy lately,” he said during a debate. “You’ll excuse us.”

In that campaign, Mr. Sanders disclosed his tax return for only one year, 2014, which showed that he and his wife had an adjusted gross income of $205,271, largely from his Senate salary and Social Security benefits.

A picture of Mr. Sanders’s finances has already been available through his annual Senate financial disclosure filing, but the tax returns provide a precise accounting of his family’s income.

In the past three years, their income soared as a result of his book writing. Mr. Sanders’s book “Our Revolution” was published shortly after the 2016 election, and a young-adult book, the “Bernie Sanders Guide to Political Revolution,” followed the next year. Another book, “Where We Go From Here,” was published last year.

Mr. Sanders reported receiving about $840,000 in book income in 2016 and about $856,000 in 2017. Ms. Sanders listed about $106,000 in income as a book author in 2017.

Tax returns released by other Democratic presidential candidates showed that they have also earned more than a vast majority of American households in recent years. Senator Kamala Harris of California and her husband reported an adjusted gross income of about $1.9 million last year, while Senator Elizabeth Warren of Massachusetts and her husband had $846,394 in adjusted gross income.

In an interview with The New York Times last week, Mr. Sanders acknowledged that he had joined the ranks of millionaires.

“I wrote a best-selling book,” he said. “If you write a best-selling book, you can be a millionaire, too.”