The "buy the demographics" bull thesis on cruiselines is not looking as good these days. Per Cruise Lines International, the average age of cruiser is 49 years old. An analysis of population trends in the core cruiser age group of 47-51 shows decelerating growth from 2007-2014, troughing at negative growth beginning in 2012. On a positive note, contribution from the older set should grow at a healthy clip as population trends are very favorable for ages north of 50.