Hillary Clinton landed her 2,383rd delegate supporter on Monday, making the former secretary of state the first woman to come so close to the U.S. presidency.

According to a delegate count Monday by the Associated Press, Clinton reached the shoo-in number after a sweeping victory in Puerto Rico and a raft of declared support from Democratic superdelegates, party insiders and office holders who can vote either way come the Democratic National Convention in Philadelphia late next month.

Clinton also leads Vermont Sen. Bernie Sanders in the popular vote by more than 3 million, according to the latest tally from RealClearPolitics.

"It's time to stand behind our presumptive candidate," Michael Brown, one of two superdelegates from the District of Columbia, told the AP. Brown recently declared his support for Clinton before the city's June 14 primary. "We shouldn't be acting like we are undecided when the people of America have spoken."

Clinton’s rival Sanders can only hope for a sweeping upset in California. Wins in New Jersey and four other states on Tuesday would also help. But if Clinton maintains her popular majority, Sanders’ hope for hundreds of superdelegates to defect from their stated support would be very unlikely.

Clinton has 1,812 pledged delegates and the support of 523 supers. Sanders has 1,521 pledged delegates and 48 supers. Only 95 superdelegates remain publicly uncommitted, according to the AP survey. None of the committed supers have defected since the AP began surveying them in late 2015.

Sanders has no chance of getting to 2,383 based on the uncommitted superdelegates and the remaining available pledged delegates. Sanders has said he will fight to the end for the nomination.

The Democrats will hold their convention on July 25-28. The Republicans will confirm Donald Trump as their nominee a few days earlier, on July 15-21, in Cleveland.