*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19722
19730
19740
19750
19760
19770
19780
19791
19800
19810
19820
19831
19843
19850
19864
198713
198813
19892
19906
19914
19921
19936
19940
19950
19964
19971
19980
19991
20001
20011
20021
20031
20041
20052
20060
20070
20083
20090
20101
20110
20120
20130
20140
20150
20161
20170
20181
20190
Total75