*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19831
19844
19851
19860
19870
198810
19892
19901
19913
19923
19936
19943
19957
19963
19978
199823
19998
20002
20012
20021
20032
20040
20056
20060
20071
20083
20092
20102
20111
20120
20130
20145
20150
20160
20170
Total111