*Excludes Observations that spanned multiple years

Pre 1970251
19702
19715
19722
19733
197421
197515
19763
19777
19786
19790
19801
19811
19821
19831
19844
19850
19863
19871
19880
19891
19901
199166
199222
199385
1994121
1995269
1996212
1997231
1998279
1999277
2000320
2001603
2002638
2003660
2004729
2005225
2006350
2007156
2008173
2009199
2010260
2011120
201270
201393
201463
201562
201674
201715
20180
Total6701