WASHINGTON—The number of Americans applying for unemployment benefits tumbled last week to 576,000, a post-COVID low and a hopeful sign that layoffs are easing as the economy recovers from the pandemic recession. The Labor Department said Thursday that applications plummeted by 193,000 from a revised 769,000 a week earlier. Jobless claims are now down sharply from a peak of 900,000 in early January and well below the 700,000-plus level they had been stuck at for months. The decline in unemployment claims coincides with other evidence that the economy is strengthening as pandemic business restrictions are lifted in many states and Americans appear increasingly willing to travel, shop, eat out and otherwise spend again. In March, employers added a healthy 916,000 jobs, the most since August, and the unemployment rate fell to 6 percent, less than half the pandemic peak of 14.8 percent. For the week ending March 27, 16.9 million …