Former Vice President Joe Biden and his wife, Jill, earned more than $15 million in the two years after leaving the White House in 2016, according to tax returns released by his campaign Tuesday. The Bidens reported an adjusted gross income of about $11 million in 2017, and $4.6 million last year. The couple previously made $396,456 while Joe Biden served in the Obama administration in 2016. Out of the Democratic nominees who have released their tax returns so far, Joe Biden has earned the highest income. Sen. Kamala Harris of California and her husband reported the next highest income, earning $3.4 million over the same two-year period. The New York Times reports that six-figure speaking engagements and a deal to write a set of books boosted the Bidens’ income after leaving office.