The percentage of veterans without jobs dipped once again in May as the national unemployment rate hit its lowest mark in 18 years.

The unemployment rate for post-9/11 veterans hit 4.2 percent last month, down from 4.9 percent in April, according to the latest Bureau of Labor Statistics figures released today. Overall veteran unemployment ticked down from 3.7 percent to 3.4 percent. Meanwhile, the comparable nonveteran employment rate saw a slight change from 3.5 percent to 3.4 percent.

Experts warn against putting too much stock in the monthly veteran unemployment numbers, which can be volatile since the data is drawn from a smaller sample size than the overall population.

Nationally, the U.S. charted a 3.8 percent unemployment rate in May — the lowest since 2000. In April, the national unemployment rate hit 3.9 percent after six straight months at 4.1 percent. Overall, the U.S. added 223,000 jobs last month, primarily in the retail trade, health care and construction industries.