*Excludes Observations that spanned multiple years

Pre 197024
19700
19710
19720
19731
19740
19751
19760
19771
19780
19790
19800
19811
19820
19831
19841
19851
19864
19870
19880
19891
19901
19910
19920
19930
19941
19958
19961
199713
199811
199912
20000
20011
20026
2003640
200431
200562
20067
20079
20089
200963
20107
20111
20120
20130
20148
201510
201618
20174
20180
Total959