Actually what the data says is the older you get the more deadly it is and below certain ages it's less than 2.

There are actually 5 episodes on "this week in virology". These people are virology professors in the US.

This episode an interesting look at the percentages.

http://www.microbe.tv/twiv/twiv-588/

EDIT: two other interesting aspects, over 80% of the cases were mild and over 50% of chinese males smoke.