*Excludes Observations that spanned multiple years

Pre 197048
19700
19710
19720
19730
19740
19750
19761
19770
19780
19790
19802
19812
19823
19832
19840
19850
19860
19871
19880
19891
19902
19913
19921
19938
199412
199514
199610
199710
19986
19998
20004
20017
20027
200312
20046
20057
20068
20074
20087
20094
20107
20119
201220
201314
20148
201516
20165
20178
201814
201915
20209
20210
Total325