*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19815
19820
19830
19840
19850
19860
19870
19881
19891
19900
19916
19921
19931
19940
19952
19961
19971
19980
19990
20001
20010
20023
20030
20042
20051
20063
20071
20080
20090
20101
20111
20122
20131
20141
20151
20160
20170
20181
Total39