Every few months, Gallup asks voters if they identify as Democrats, Republicans, or something else. For respondents who say they are something else, they are then asked if they lean toward either the Republican Party or the Democratic Party.
During the last few months, the percentage of voters who identify as Democrats, or who say they lean toward the Democratic Party, has remained the same, at 45%. The percentage of voters who identify as Republicans, or who say they lean toward the Republican Party, has dropped from 40% to 38%. See the results here. The poll was taken during May but only released on June 6. Thanks to Political Wire for the link.