*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19854
19860
19870
19880
19890
19900
19910
19920
19930
19940
19955
19961
19979
19987
19993
20002
20016
20020
20035
200429
200528
200625
200729
200812
20092
20104
20111
20121
20130
20140
20150
20160
20170
Total173