*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19802
19810
19820
19830
19840
19850
19860
19870
19880
19890
19900
19910
199230
19934
19941
199537
19962
19974
19983
19990
20002
20010
20021
20032
200413
200523
20063
20070
20082
20090
20100
20110
20120
20130
20141
20150
20160
201712
Total142