*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197212
19733
19740
19750
19760
19770
19780
19791
19800
19810
19820
19830
19840
19850
19860
19871
19885
19890
19904
19914
19924
19937
19940
19954
19966
199710
19983
19996
200011
20011
20023
20030
20040
20050
20060
20070
20081
20092
20100
20110
20120
20131
20140
20150
20160
20170
20180
20190
Total89