U.S. consumer confidence rose again this month, hitting a new 18-year high.

The Conference Board said Tuesday that its consumer confidence index climbed to 137.9 in October from 135.3 in September. Both readings are the highest since September 2000.

The index measures consumers' assessment of current economic conditions and their outlook for the next six months. Both improved in October.

"Consumers do not foresee the economy losing steam anytime soon," said Conference Board economist Lynn Franco. "Rather, they expect the strong pace of growth to carry over into early 2019."

The share of respondents saying that jobs are "plentiful" rose this month to 45.9 percent, highest since January 2001.

Consumers' spirits have been lifted by a strong labor market. Unemployment has dropped to 3.7 percent, lowest since 1969. The government reported Friday that consumer spending from July through September was the strongest in nearly four years.

In a research note, Jennifer Lee, senior economist at BMO Capital Markets, called the October uptick in confidence "pretty impressive, given the wild swings in the stock market this month ... At the end of the day, it is the job market, or the security of having a job with a regular paycheck, that supports confidence and spending. So far, so good."

Economists monitor confidence because consumer spending accounts for about 70 percent of U.S. economic output.