WASHINGTON — The number of Americans seeking unemployment aid plummeted to a five-year low last week, a hopeful sign the job market may be improving. But much of the decline reflects seasonal volatility in the data.
Weekly unemployment benefit applications fell 37,000 to a seasonally adjusted 335,000, the Labor Department said Thursday. That’s the lowest level since January 2008, just after the recession began.
The four-week average, a less volatile measure, fell to 359,250.
The data can be uneven in January. Job cuts typically spike in the second week of the month as retailers, restaurants, and other companies lay off temporary workers hired for the holidays. The department seasonally adjusts the numbers to account for such trends, but the data can still be choppy.
Last week, the layoffs weren’t as numerous as expected, a department spokesman said. That caused a steep drop in the seasonally adjusted data.
The broader trend will become clearer in the coming weeks. Applications were declining slightly at the end of last year, pushing the four-week average to a four-year low in the last week of December.
The applications figures ‘‘suggest the labor market is getting better, the issue remains the extent of the improvement,’’ said Joseph LaVorgna, an economist at Deutsche Bank.
Applications are a proxy for layoffs. Overall, applications remain at a level that suggests employers are hiring at a slow but steady pace. Applications fluctuated between 360,000 and 390,000 for most of last year. At the same time, employers added an average of 153,000 jobs a month.
That’s just been enough to slowly push down the unemployment rate, which fell 0.7 percentage points last year to 7.8 percent.
Employers added 155,000 jobs last month, nearly matching the average for the year. December’s steady job gain suggests employers didn’t cut back on hiring in the debate over the tax and spending changes known as the fiscal cliff.