Polls are showing that Sen. Bernie Sanders' popularity is dropping among all voters over the past few months, even after he was able to hold onto most of the popularity he enjoyed during his 2016 presidential race through the end of last year.

According to a new CNN poll, Sanders' favorable rating is at 46 percent among registered voters, compared to an unfavorable rating of 45 percent, reports CNN.

Meanwhile, a Quinnipiac University poll from late in December gave the Vermont Independent senator and 2020 Democratic presidential candidate a net favorability rating of plus two points, and an average of recent polls puts his net favorability at minus one point.

When Sanders' presidential bid ended in 2016, he had a 59 percent favorable rating, compared to a 36 percent unfavorable rating among voters in a CNN poll in June 2016.

Even in December 2018, a CNN poll gave the senator a plus 13 net favorability rating, and a Gallup poll in September put him at plus 15.

Sanders' net favorability, though, is at about the same place as the numerous others who have declared their candidacy for the 2020 nomination, even though he does enjoy more name recognition than many of the other contenders.

He also may need to show that he is electable against President Donald Trump. According to the newest CNN poll, 30 percent of Democratic voters think their party has a better chance of winning with him as the nominee, but 59 percent think a different candidate would be more likely to win.