(CNN) One of the best ways to gauge the relative health of a political party's brand is to see how willing people are to say they identify with the party. Which is why new Gallup poll numbers on party identification should worry Republicans heading into an election year.

Just 37% of people identify as Republicans or leaning toward the Republican Party, compared with 44% who identify as either leaning toward the Democratic Party or as solid Democrats. Another 14% say they are independents and don't lean to either party.

What's particularly worrisome for Republicans is the trend line on the party ID question since President Donald Trump was elected in November 2016.

At that point, 44% called themselves Democrats while 42% said they were Republicans. It's been all downhill for Republicans since then.

How do these numbers compare to the composition of past electorates, according to exit polls? In 2016 , Democrats composed 36% of the electorate, as compared to 33% for Republicans and 31% for independents. In 2014 , it was 36% Republican, 35% Democratic and 28% independent. In 2012, Democrats made up 38% of the electorate while Republicans were 32% and independents were 29%. In 2010 , Republicans and Democrats each were 35% of voters while independents were 29%. And in 2008 , it was Democrats -- 39%, Republicans -- 32%, independents -- 29%.

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