*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
19902
19910
199230
19934
19941
199537
19963
19974
19983
19990
20002
20010
20021
20038
200420
200529
200610
200712
20083
20096
20108
20117
20128
201317
201415
201516
201620
201725
20181
Total294