*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19831
19840
19851
198611
19870
19880
19891
19902
19913
19920
19934
19948
199513
19961
19975
199823
19992
20007
200114
20028
20031870
2004394
2005954
2006196
2007736
2008216
20091194
201020
201116
20124
20130
20145
201515
201617
201730
20180
Total5772