New claims for unemployment benefits dropped 15,000 to 233,000 in the second week of July, the Department of Labor reported Thursday, the lowest level since mid-May.

Investors had expected that jobless claims would remain about steady from the previous week, around 246,000.

Low jobless claims are a good sign because they suggest that layoffs are rare. Investors value the claims numbers because they are published weekly, providing an up-to-date look at the labor market.

In recent months, historically low levels of claims have provided one of the most encouraging signs of the health of the U.S. economy.

In fact, Thursday's numbers underline that, in some parts of the country, labor shortages are becoming an issue.

For 13 straight weeks through early July, there were fewer than 2 million people receiving unemployment benefits of all durations. Benefits are available for up to 26 weeks in most states.

That is a streak not seen the end of 1973 and the beginning of 1974, when Ricahrd Nixon was president and the U.S. population was much smaller than it is today.