The Pew Research Center study found those using the micro-blogging platform are more likely to come from higher-income brackets but that their gender and racial or ethnic makeup is largely similar to the adult population as a whole.

The Pew analysis indicates that the 22 percent of American adults use Twitter -- far less than the 69 percent using the leading social network Facebook.

Twitter users are younger, more likely to identify as Democrats, more highly educated and have higher incomes than US adults overall, Pew researchers found.

The median age of adult US Twitter users is 40 -- seven years younger than the overall population.

The survey found 42 percent of adult Twitter users have at least a bachelor's degree, compared with 31 percent for the general public.

And 41 percent had a household income above $75,000 -- nine points greater than the general population.

The researchers found 36 percent of those surveyed identify with the Democratic Party, compared with 30 percent of all US adults, while 21 percent said they identified with Republicans, in contrast with 26 percent of the US population.

Only 14 percent of Twitter users characterized their political views as "very conservative" compared with 25 percent of the overall population.

Similar shares of Twitter users and US adults identify as "very liberal."

The survey found 90 percent of Twitter users rarely tweet, while the active 10 percent are responsible for 80 percent of all tweets created by US users.

The median Twitter user posts two tweets a month, follows 89 accounts and has 25 followers.

The "active" tweeters are much more likely to be women -- who make up 65 percent of this group -- and more likely to say they regularly tweet about politics, according to the researchers.

The survey comes amid intense pressure from President Donald Trump and his Republican allies who claim that Twitter and other social platforms are biased against conservatives -- a claim roundly rejected by the companies.

Pew surveyed 2,791 US adults in November and December 2018 who were willing to share their Twitter handles -- enabling the researchers to analyze the content from their accounts. The margin of error for the study was estimated at three percentage points.