*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19741
19750
19760
19770
19780
19791
19800
19810
19820
19830
19840
19852
19863
198731
198876
198911
19903
199143
199214
199312
19943
199533
19968
199722
19981
19998
200015
20011
20025
20030
20042
20050
20061
20070
20087
20099
20102
20111
20120
20131
20142
20155
20161
20170
20180
20191
20200
20210
20220
Total325