If I understand your graphic correctly, the "E" in "VEP" means "eligible", and the number of eligible voters (1.8 million) includes those who are registered, and those who could be registered if they chose to do so.
According to the Nevada State website, there were about 1.2 million registered voters in October, 2006. Note also that they distinguish between total registered voters and active voters.
This link provides an explanation of "active" and "inactive" voters.
So, you have 1.8 million eligible voters, 1.2 million registered voters, and just under 1 million "active" registered voters.
The total turnout percentage figures that appear here for the 2006 elections use the active registered voter number, and show a total turnout of 59%.
If you use the total registered number, you get 49%, and if you use eligible voters, you get 33%.
For whatever reason, the turnout numbers that are being circulated are based on active registered voters, and they will always show higher turnout rates.
I am in no way saying that there was no fraud in the recent election, only that these high turnout numbers are not the smoking gun that would prove it.
Apples and oranges indeed. "Active registered voters" is a misleading figure in IMO, and in my view, the majority of statisticians who track voting also put emphasis on the bottom line by using the total of all state registered voters.
In another example,
'The PEW Center of States' said in 2006 that Nevada's turnout was 36.89%, which is only slightly different than George Mason University's percentage.
A quote on top of their Webpage:
"Demand for Democracy. Only 40 percent of those eligible to vote actually go to the polls in off-year elections. How can states reach the other 60 percent?"
According to the Nevada State website, there were about 1.2 million registered voters in October, 2006. Note also that they distinguish between total registered voters and active voters.
Nevada also reported 1,331,197 total registered voters in December of 2009. And On May 25, 2010 KOLO TV (AP) reported "There are 1.3 million registered voters in Nevada as of the end of April."
http://www.kolotv.com/home/headlines/94863874.html
So the voter turnout rate for this Nevada election was really 51.28%.
*682,651 / 1,331,197 = 51.28% - is not a lot higher than Gallup's generic 45% US wide high turnout percentage.
*The 682,651 figure is the combined total votes for both Angle and Reid.
The 51.28% doesn't set off my BS meter like the widely reported 64.5% figure does in this mid-term senate race.