Kamala Harris and her husband earned more than twice as much as Joe Biden and his wife did last year, according to copies of their income tax returns released on Friday.

Harris and the so-called second gentleman, Doug Emhoff, reported a federal adjusted gross income of about $1.7m in 2021, which was about the same they claimed to have earned the prior year.

Joe Biden and the first lady, Jill Biden, cited an income of nearly $611,000, about $4,000 more than they made in 2020, said their tax documents, which were released by the White House.

The vice-president and her husband also reported paying $523,371 in taxes on their income, a rate of 31.6%. For their part, the Bidens reported being taxed $150,439 on their income, meaning the president’s family’s tax rate was 24.6%.

Nearly $772,000 of the income that Harris and Emhoff reported stemmed from the sale of a condominium in San Francisco and pay she earned as a writer, the tax documents show. The couple reported donating $22,100 to charity last year, with the Bidens reporting $17,394 in charitable giving.

The Bidens’ largest charitable gift – $5,000 – went to the Beau Biden Foundation, a public charity which is named after the president’s late son and is dedicated to protecting children from abuse. Nine other groups divvied up the balance of their charitable donations.

For their part, Harris and Emhoff reported donations of $5,000 to three schools which they attended: California State University, Northridge; Howard University; and the University of Southern California.

A White House statement accompanying Friday’s release of documents made it a point to say Joe Biden had now shared 24 years’ worth of tax returns with the public, a move “once again demonstrating his commitment to being transparent with the American people about the finances of the commander in chief”.

Harris, meanwhile, had now published 18 years of tax returns, the White House’s statement noted.

Donald Trump, Biden’s presidential predecessor whom he defeated in the 2020 election, never released his tax returns.

Last year, however, the New York Times obtained decades of Trump’s tax information and reported on it. That reporting showed, in part, that Trump paid no income taxes in 11 of 18 years that the Times examined.

Harris released her tax returns hours after she met with Tanzania’s president, Samia Suluhu Hassan. Biden earlier had announced plans to visit the Pacific north-west amid falling approval numbers as this November’s midterm elections approach.

Full copies of the president’s and vice-president’s tax returns are available online.