*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19831
19840
19850
19860
19873
19880
19893
19901
19910
19926
19936
19944
199528
19966
19979
19988
199916
20000
20014
20020
20030
20040
200517
20066
200714
20086
20097
20100
20110
20120
20130
20140
20150
20160
20170
Total145