*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19843
19850
19860
19870
198812
198922
19903
19915
19923
199310
19942
199532
19963
19970
19981
19993
20009
20015
200212
20031
20041
20052
20060
20070
20081
20090
201022
201128
20126
20139
20146
20150
20162
20170
Total203