Of the many issues dealing with the Askani timeline, only one (X-Force #17) uses a year number. All other books say about two millennia in the future.
The other year numbers are all to be seen in relation to 3806, the quoted year from X-Force #17. The assumptions are based on dialogue and character ages. For example Mother Askani said she lost the Phoenix Force nearly eighty years ago, or Tyler at least being 15-20 years old upon his capture by Stryfe.
ca. 3680 - 3700 Rachel arrives in the future, pulls Tanya Trask out of the timestream, befriends Blaquesmith, starts Askani movement
ca. 3760 - 3765 baby taken to the future, cloned because of techno-organic infection, Mother Askani transports the consciousnesses Jean and Scott to the future
ca. 3770 - 3775 Apocalypse is defeated by the Dayspring family and perishes, Jean and Scott return, Mother Askani dies
ca. 3780 - 3785 Nathan finds Aliya among last Askani, together with Tetherblood they organize Clan Rebellion
ca. 3800 - 3805 Aliya killed, Tyler captured and brainwashed by Stryfe
3806 Canaanite forces assume global control, Stryfe travels to the 20th century with Zero, Cable follows
ca. 3810 - 3815 Cable takes Garrison Kane to the future, Clan Chosen destroys Canaanite timex unit