This is the third column on key demographics to follow in the Presidential race this year. I am basing my analysis on aggregating online and telephone surveys conducted by JZ Analytics since January. Percentages below are based on a total sample 5300 likely voters. In the overall horse race, President Barack Obama leads former Governor Mitt Romney 44% to 40%, with 15% undecided. It is a close race but there are some fascinating figures behind the overall numbers.

Income: Just as Romney won the GOP nomination by triumphing consistently among voters earning $100,000 a year or more, he leads Obama in this category by 3 points - 47% to 44%. This highest income category represents about 13% of all likely voters in my sample and is key to any Romney victory. What is perhaps more significant is that Romney leads by 6 points among the all-important $50,000-$75,000 income group, 42%-36%. They are larger - 21%-- of all voters and it is the group that normally provides the winner in presidential elections going back to 1972. With these aggregated numbers, Romney is outperforming Senator John McCain's totals in 2008: McCain won this income group by just 1 point-49% to 48%. Small wonder that the Obama campaign is ferociously attacking Romney's record as an "outsourcer in chief" because voters in this income group are on the front lines of lost manufacturing jobs. At some point, however, Obama will have to attempt a positive message to demonstrate why he should at least match his numbers among this group from 2008. He currently is 12 points short.

College Education: Voters with at least a college degree are at least 40% of all likely voters. Here is where Obama does very well leading Romney by 8 points - 47% to 39%. This matches his 8 point margin over McCain (53%-45%) in 2008 and other indicators suggest he will do well again. His approval rating among college graduates is slightly higher than his overall rating from all voters and slightly more than the average feel he deserves re-election.

International Travelers: One in three voters has an active passport. While the president's overall job approval from our large sample is 46%, voters with passports give him a rare 50% rating. And overall, only 40% of voters believe that Obama deserves re-election, 43% of those with passports feel he should get another four years. This group gives Obama a 10 point lead over Romney - 48% to 38%. (There are no figures from exit polls on voters with passports for comparison purposes).

The picture that emerges from these select numbers is one of dissatisfaction among voters with the highest income, but an incumbent who might be able to cut his losses among more upscale voters by appealing to those with college degrees and those who have a more international perspective. At the same time, the president is waging an all-out war against Romney to win over middle income voters who, at the moment, are really enamored with Obama. An incumbent presently winning only 36% of voters in the $50,000 to $75,000 income range spells potential trouble for him.