*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19904
19913
19929
19933
19942
19958
19964
19975
19986
199912
200021
200110
20028
200318
200413
200518
20066
20077
20086
20094
20102
20111
20121
20131
20140
20150
20160
20170
Total173