A papery give away

Visiting Bianca's page today at http://www.goodnightlittlespoon.com/ I read that she was giving away some mail art supplies to decorate envelopes.

But in order to win one of these gorgeous set, it was required to guess how many envelopes there are/were in her basket. She said it was in between 1 and 100 :

I would say 37. What do you think ? Am I close to the right figure ? Keep your fingers crossed for me, please ...