*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19752
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19906
19913
19925
19932
19940
19953
19966
19971
19981
19995
200016
20016
20027
200317
200419
200512
20066
20071
200812
20093
20105
20114
20124
20131
20140
20150
20160
20170
Total147