*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19834
19840
19850
19862
198711
19880
19890
19901
19912
19925
19938
19943
19952
19960
19970
19980
19991
20003
20015
20023
20030
20046
200510
20060
20073
20081
20090
20100
20110
20120
20130
20140
20150
20162
20170
Total73