Just 3.4 percent of Americans will decide who controls the Senate after this election

* about 230 million Americans are of age to vote.

* But only about 217 million of those within the right age range are eligible to vote, thanks to restrictions like felony ineligibility.

* About 65 percent of those who are eligible to vote are actually registered to vote,

* and midterm elections usually see only about 42 percent voter turnout from the pool of eligible votes — about 90 million in 2010.

* 34 states will have Senate elections this year, thanks to the rotating system of Senate terms,

* But only about eight states have hotly contested races that will decide whether the GOP retakes the Senate: Alaska, Arkansas, Colorado, Iowa, Louisiana, Kansas, New Hampshire, and North Carolina.

* Just 11 million people are likely to turn out to vote for Senate races in those states this November,

* which means that roughly 3.4 percent of the total population of the United States will decide who controls the Senate in 2015.