A dramatic shift in party preference toward Republicans happened during 2021.
Democrats had a 9 percentage-point advantage in the first quarter of 2021. But by the fourth quarter Republicans had a 5 point edge. That's a swing of 14 percentage points in less than a year.
That information is according to Gallup, which aggregated data from telephone surveys during 2021, including interviews with more than 12,000 randomly sampled adults.
Gallup says that, "both the nine-point Democratic advantage in the first quarter and the five-point Republican edge in the fourth quarter are among the largest Gallup has measured for each party in any quarter since it began regularly measuring party identification and leaning in 1991."
Overall averaged numbers in 2021 showed that 29% of Americans identified as Democrats, 27% as Republicans and 42% as independents.
Seventeen percent (17%) of those Independents indicated they lean toward the Democrat Party and 16% said they lean toward the Republican Party.
Overall, 46% of adults identify as Democrats and 43% identify as Republicans.