*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19881
19890
19900
19911
19927
19936
199410
199510
19960
199716
19981
19991
20002
20012
20020
20030
20043
200514
20060
20073
20080
20090
20100
20110
20121
20132
20140
20150
20160
20171
Total81