*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19761
19770
19780
19790
19801
19810
19820
19830
19840
19850
19860
19870
19880
19890
19901
19910
19921
19930
19941
19951
19961
19974
19982
19998
200018
200122
200228
200368
200458
2005140
2006120
200716
200847
200990
2010110
201155
20124
20133
20147
201531
20161
20170
20180
Total840