The U.S. mortgage delinquency rate rose to 7.76% in May as Americans struggled to pay their bills during the worst public health crisis in more than a century.

The rate rose from 6.45% in April and was 3.39% in March, the month when states began issuing stay-at-home orders to try to stem the spread of COVID-19, according to the report on Monday. Black Knight counts loan in forbearances – meaning they have an agreement with the servicer to suspend payments – as being delinquent, as does Mortgage Bankers Association.

Measured as a number, rather than a percentage, there were 4.12 million mortgages in the U.S. that had payments more than 30 days overdue in May, Black Knight said.

Last week there were 4.6 million homeowners with mortgages in forbearance, down 57,000 from the prior week, according to Black Knight. Some owners get an agreement with their servicers to suspend payments and then keep paying their home-loan bill, the firm has said in the past.

Mississippi had the worst delinquency rate, at 12.73%, according to the report. Louisiana was next, at 11.79%, followed by New York at 11.28%, New Jersey at 11.03% and Florida at 10.52%.

The states with the lowest delinquency rates were Idaho at 4.4%, Washington at 4.91%, South Dakota at 5.02%, Oregon at 5.12%, and Montana at 5.13%.

Serious delinquencies, which means people who are 90 days past due but not yet in foreclosure, have increased by more than 50% over the past two months to 631,000, Black Knight said.

There’s a moratorium on foreclosures for loans that are backed by Fannie Mae, Freddie Mac, and the Federal Housing Administration through the end of August because of the COVID-19 pandemic.