Which is more popular: Mother's Day or Valentine's Day?

I've never read any research on this topic, but looking at the traffic graphs for these online flower shops, they must make over 90% of their money on the two big flower holidays, Valentine's Day and Mother's Day. Which is bigger? You'll have to take a guess, and then find the answer on these traffic graphs:

1800flowers.com - Graph
FTD.com - Graph
ProFlowers - Graph

P.S. Don't forget your mom this Sunday.