Why all of the sudden am I getting these scam emails?

Everyday when I check my email, I read about 2-3 of these "You won the lottery in the UK" or "A distant relative named you as a beneficiary for their estate, just send us your name, occupation, number, address, etc..." and several from a Nigerian "bank". I know these are scams but how are they finding my email address and why all of the sudden and recently am I being bombarded with this crap? Its everyday with this crap!