*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19756
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19901
19911
19923
19930
19948
19951
19963
19972
19984
19991
20000
200110
20026
20030
200463
20059
20068
20074
20086
200984
201022
201110
20128
201314
20141
20150
20160
20170
Total275