By PAUL WISEMANWASHINGTON (AP) â¿¿ The number of Americans seeking unemployment benefits jumped by 16,000 last week, the second straight weekly increase. But the longer-term trend in layoffs remained consistent with an improved job market. Applications increased to a seasonally adjusted 357,000 for the week ending March 23, the Labor Department said Thursday. That's up from 341,000 the previous week, which was revised slightly higher. The four-week average, a less volatile measure, rose 2,250 to 343,000. Even with the gain, the average is only slightly higher than the previous week's five-year low of 340,750. Economists pay closer attention to the four-week average because it smooths out week-to-week fluctuations. Despite the two weeks of higher initial unemployment claims, "the overall trend of stronger labor market growth continues," Jennifer Lee, senior economist at BMO Capital Markets, wrote in a note to clients. First-time applications are a proxy for layoffs. They have been declining steadily since November. At the same time, hiring has accelerated, lowering the unemployment rate in February to a four-year low of 7.7 percent. Unemployment benefit applications surged during the recession as companies slashed millions of jobs. The number of people seeking aid averaged only 320,000 a week in 2007. That figure soared to 418,000 in 2008 and 574,000 in 2009. But as layoffs and firings eased, applications for unemployment aid slowly but steadily came down. They fell to 459,000 in 2010, 409,000 in 2011, and 375,000 last year. Through the first 12 weeks of this year they are averaging roughly 353,000. The total number of people receiving some kind of unemployment aid is also down sharply. Nearly 5.5 million people were receiving unemployment aid as of the week ended March 9, the latest data available. That's up roughly 87,000 from than the previous week but still well below the 7.2 million from a year earlier. The data on total unemployment benefit recipients are not seasonally adjusted and are volatile.