LOS ANGELES - A resurgent housing market, rising home values and steady job gains are helping more U.S. homeowners stay on top of their mortgage payments.

The percentage of mortgage holders at least two months behind on their payments fell by 21 percent in the first three months of this year versus the same period in 2012, credit reporting agency TransUnion said Wednesday.

The sharp annual decline in the mortgage delinquency rate represents the biggest quarterly drop on record for TransUnion, whose data go back to 1992.

"We certainly expected improvement this quarter, as the housing sector is in recovery, but the magnitude of the improvement was unexpected," Tim Martin, TransUnion's group vice president of U.S. housing, said in a statement.

All told, the mortgage delinquency rate was 4.56 percent in the first quarter. That's down from 5.78 percent in the prior-year quarter, TransUnion said.

The first-quarter rate also fell 12 percent compared with the last three months of 2012, when it was 5.19 percent, a four-year low.

Even so, the mortgage delinquency rate is still above the 1 percent to 2 percent average historical range, an indication that many homeowners still are struggling to make their payments.

Before the housing bust, mortgage delinquencies were running at less than 2 percent nationally. They peaked at nearly 7 percent in the fourth quarter of 2009.

The rate has been trending down since then, aided by a rebound in home sales and rising home prices that began gaining traction about a year ago.

U.S. home prices rose 10.5 percent in March compared to a year earlier, the biggest gain since March 2006, according to real estate data provider CoreLogic. March marked the 13th month in a row that home prices have increased on an annual basis nationwide.

Rising home values make it easier for borrowers to refinance their mortgages or sell their homes if they lose their jobs or otherwise become unable to make payments. They also help bring down the number of homeowners who are underwater on their mortgage, or owe more on their home loan than their homes are worth.

Last year, 1.7 million homeowners who had been underwater on their mortgage were moved into positive equity, according CoreLogic. That left another 10.4 million, or nearly 22 percent of all homes with a mortgage, still in negative equity at the end of last year.

Steady job growth also has helped.

Employers have now added an average of 208,000 jobs per month from November through April. That's much higher than the average of 138,000 in the previous six months. And the national unemployment rate, while still elevated, fell last month to 7.5 percent from 7.6 percent in March.

Every state and the District of Columbia posted an annual decline in the late-payment rate of home loans in the first quarter, with Arizona leading the way. The state's mortgage delinquency rate was 4.3 percent, down nearly 38 percent from a year earlier, TransUnion said.

California, with a rate of 4.2 percent, and Colorado (2.7 percent) also had steep annual declines in the rate of late payments.

Florida, a foreclosure hotbed throughout the housing downturn, clocked in with the highest mortgage delinquency rate in the nation for the January-March quarter at 11 percent - but that's down nearly 21 percent from the same period last year, the firm noted.

Nevada (9.1 percent), New Jersey (6.9 percent) and Delaware (6.3 percent) rounded out the top four states with the highest late-payment rate.

Meanwhile, mortgage debt per borrower dipped about 1.2 percent to $186,018 in the first quarter from a year earlier, and was essentially flat with the previous quarter, the firm said.

TransUnion, which draws its data from a sample of 27 million consumer records, anticipates the national mortgage delinquency rate will continue to decline in the current quarter to about 4.5 percent.

"There is no reason to believe the decline in mortgage delinquencies will not continue," Martin said. "We do not know if the first quarter was a blip, or if it's the beginning of a more rapid decline."