*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
19880
19890
19904
19911
19920
19931
19940
199511
199612
19973
19980
19992
20007
20018
20021
20030
20041
20050
20060
20070
20080
20090
20101
20112
20120
20130
20141
20151
20160
20170
20183
20191
20200
20210
20220
Total60