How many times per day do you check email? An infograph from Constant Contact estimates that 72% of people check email six or more times daily. By the end of this year, there will have been more than 200 billion "permission-based emails" sent in the U.S. The infograph provides insight into these stats and more -- including the estimate that each email address gets 3 permission-based email messages per day, up from 2 in 2009.