According to this Marvel timeline:
"Early" scenes of X-Men: Days of Future Past are set.
Mark I Sentinels are created. Between 1973 and 1996, Trask produces 8,732 Mark I Sentinels for the governments of the United States, China, Russia, Israel, Saudi Arabia, France, India and the United Kingdom.
The year that "The Wolverine" is set in.
Mark X Sentinels announced.
Professor X and Magneto meet Wolverine at an airport.
"Future" scene of X-Men: Days of Future Past are set.
So effectively, X-Men: Days of Future Past contains scenes from 1973 and 2023. The Wolverine end credit scene takes place in 2015.