Washington (CNN) With the final primaries of the 2016 nomination season approaching, a new CNN Poll of Polls finds the candidates most likely to lead their parties into the general election are locked in a tight contest. Hillary Clinton holds an average of 45% support while 43% back Donald Trump across five recent nationwide polls of registered voters.

The Poll of Polls suggests a vastly different race than many anticipated.

Throughout March and April, public polling on the presidential race found Clinton well ahead of Trump, with the former secretary of state holding double-digit leads over the businessman in 10 out of the 14 polls that met CNN's standards for reporting in those months.

A string of polls released in the last two weeks, however, suggest a much tighter contest. For the most part, those tightened margins come from a more unified Republican Party. Across the five polls included in the Poll of Polls, Clinton averaged 6% support among self-identified Republicans. Polls from the same organizations in late-March and April found Clinton averaging 12% support among Republicans.