*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19901
19910
19923
19933
19941
19950
19961
19972
19981
19991
20001
20018
20022
200314
20047
20058
200622
200718
200836
20093
20108
20113
20123
20137
20140
20150
20160
20170
Total154