Age demographics skew old even for PA, one of the oldest states in the country. In 2012, 17% of the PA electorate was 65 or older. PPP has 23% of the electorate as senior citizens.
PPP also projects that 80% of the PA electorate will be white when only 78% of PA voters were white in 2012 and most of the voter population loss was older white voters while a disproportionate number of new voters in the state are non-white (especially Latino, even there)
You are going by the exit polls when you say PA electorate was 78% white in the last election. There is a lot of accurate analysis (Nate Cohn's linked below) showing that the electorate was whiter and older nationally than the exit polls indicated in 2012 and beyond. Simply put Obama did better with blue collar whites and whites in general than exit polls presented. Romney probably won only 56-57% instead of 59% of whites.
Can't include a link due to under 20 posts but google Nate Cohn's article "There Are More White Voters Than People Think." Its a pretty open and shut case, local voter file data and the CPS survey show that the electorate was probably 74-75% white nationally in 2012 and will be 72-73% white this year.
