The volume of travel marketing emails sent during the 2015 holiday increased 68 percent over 2014, according to a new report from Experian. The Q3 2015 Email Benchmark Report also revealed that email volume from multichannel retailers was up 36.4 percent this holiday season. Across industries, the peak volume days from the Wednesday before Thanksgiving through the Tuesday after Cyber Monday, transactions were 22 percent higher than those seen last year.