WASHINGTON (MarketWatch) — The number of Americans who applied for unemployment benefits last week sank to a 15-year low, a sharp drop potentially tied to seasonal quirks but one that also reflects the low level of layoffs occurring in the U.S. economy.

Initial jobless claims in the period stretching from April 19 to April 25 fell to a seasonally adjusted 262,000 from a revised 296,000 in the prior week, the Labor Department reported Thursday. That’s much bigger than Wall Street expected.

The four-week average of new claims dropped a smaller 1,250 to 283,750. The monthly average smooths out sharp fluctuations in the more volatile weekly report and is seen as a more accurate predictor of labor-market trends.

The plunge in the weekly jobless claims — a proxy for layoffs — is a welcome sign but should be treated with caution because. The report tends to be very jumpy from late March until the end of April because of difficulties trying to seasonally adjust the numbers to account for spring break and Easter holiday that often occurs weeks apart from one year to the next.

This year, for example, Easter took place on April 5. In 2014, the holiday fell on April 20, and the year before that Easter was celebrated on March 31. Spring break also can distort the report — bus drivers and cafeteria workers in some states can file for benefits in the week school is out.

Still, the level of new claims has stayed below the key 300,000 level for eight straight weeks, a sign layoffs remain extremely low even as hiring appears to have slowed since the end of last year. While the labor market is not improving quite as rapidly, companies continue to hire at a steady clip.

Next week, Wall Street will get the latest diagnosis of hiring trends with the employment report for April. Economists polled by MarketWatch predict the economy likely added 245,000 jobs, up sharply from a disappointing 126,000 preliminary increase in March.

Meanwhile, the number of Americans already receiving regular weekly unemployment checks, known as continuing claims, fell by 74,000 to 2.25 million in the week ended April 18. That also marks a 15-year low.