Cache is NOT at the posted coordinates. Solve the puzzle to find the cache!

M=2
What year did Wheels00 start caching?
2001 = N 41° 36.398' W 87° 48.435'
2002 = N 41° 37.208' W 87° 46.302'
2004 = N 41° 37.467' W 87° 45.503'
2005 = N 41° 37.201' W 87° 47.960'
2006 = N 41° 36.333' W 87° 46.463'
2007 = N 41° 35.996' W 87° 46.520'
2008 = N 41° 37.165' W 87° 46.968'
2009 = N 41° 37.204' W 87° 47.429'
2010 = N 41° 37.302' W 87° 48.002'
2011 = N 41° 36.509' W 87° 47.865'