A new poll finds that New York Mayor Michael Bloomberg’s approval rating has dipped below 50 percent for the first time in five years.

The Marist College survey was released Tuesday.

It found that 49 percent of registered New York City voters think the billionaire mayor is doing either an excellent or good job. The poll said 33 percent rate him as doing a fair job, 16 percent said poor and 2 percent weren’t sure.

The last time Marist asked this question, in April, 56 percent of voters rated him excellent or good.

They said then that Bloomberg was the city’s best mayor in 30 years.

Marist questioned 696 registered voters July 28 through Aug. 5.

The margin of error is plus or minus 4 percentage points.