I think it's more likely to happen in 2016.
I've made the argument for the historical precedent before.
https://uselectionatlas.org/FORUM/index.php?topic=176990.0I get the counterpoint that noting the trend is worthless because there are specific reasons for each time the White House changed hands. But much of that can come to specific tendencies, as politicians delay inevitable problems for a few years (but not more than that) and enough voters decide that their lives haven't been greatly improved recently, so it's time to give the other party a shot.
