This isn't an apples to apples comparison, but according to the Prince, 41.5% of the graduating seniors my year (2008) "who had accepted full-time employment offers by graduation" were employed in the "financial sector" (http://www.dailyprincetonian.com/2010/03/08/25465/).
Not an apples to apples comparison with the Yale article, but my reaction is still surprised that the number is that small at Yale.
Yale and Princeton student cultures could not be more different. Yale attracts a more ultra-liberal, save-the-world student body, whereas Princeton attracts a more ultra-conservative, make-the-money student body.
It doesn't suprise me that the original posted article came out of the Yale's student newspaper, instead of a Princeton one.