From Halopedia, the Halo wiki
(Based on the Military Calendar) 100,000 B.C.E. c. 1720 1945 2004 2160-2200 2160 2162 2163 2164 2170 2291 2310 2362 2390 2490 2494 2496 2505 2510 2511 2512 2513 2517 2519 2525 2530 2531 2535 2536 2540 2549 2550 2552
Should be put on pages that are involved with time.