It would be interesting to see the questions that were asked - phraseology is important.  
It is interesting that the Pew Center says a "more detailed study" was conducted last year - with different results.  
And it is interesting to note - which Mr. Rowe did not mention - only 14% "strongly" oppose the death penalty....which leads one to question if that means that one who opposes it would approve of it in certain circumstance.   Perhaps the question that needs to be asked is more along the lines of "do you feel that there is ever a reason to use the death penalty?"