WASHINGTON — The national unemployment rate dipped to 8.2 percent in March, but mostly because more Americans stopped looking for work.

The Labor Department said this morning that the economy added 120,000 jobs in March, down from more than 200,000 in each of the previous three months.

The unemployment rate fell to 8.2 percent, the lowest since January 2009.

The rate dropped because fewer people searched for jobs. The official unemployment tally only includes those seeking work.

The economy has added 858,000 jobs since December — the best four months of hiring in two years.

But Federal Reserve Chairman Ben Bernanke has cautioned that the current hiring pace is unlikely to continue without more consumer spending.