Unemployment sank to 4.3 percent in May, its lowest level in 16 years, the government reported Friday, but halfhearted wage growth and a shrinking labor force revealed the economy’s stubborn weak spots.

While the downsides sent bond prices lower, the report is unlikely to deter the Federal Reserve from raising interest rates when its policy makers meet in Washington this month. “It is not enough to derail the Fed at all,” said Dan North, chief economist at the credit insurer Euler Hermes North America.

The milestone on the jobless rate came with a middling increase of 138,000 in payrolls and revisions that reduced the gains in the previous two months. It mainly reflected a decline in the share of working-age adults who have a job or are in the market for one.

The judgment of what constitutes strong or tepid job growth has shifted as the expansion ages. With more baby boomers retiring each year, economists estimate that the monthly addition of roughly 100,000 jobs should be enough to absorb those entering the work force, including newly minted graduates.