*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19900
19910
19927
19931
199410
199529
199627
199712
199810
19991
20001
20015
20029
200381
20043
200588
20068
20072
200811
20096
20102
20112
20122
20133
20148
201515
2016274
2017110
20180
Total727