*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19836
19841
19851
19862
19875
198839
19896
199020
199121
199225
199326
199412
199530
19967
199723
199832
19999
20007
20019
20022
200316
20045
20059
20067
20073
20086
20095
20109
20115
20123
20130
20141
20152
201615
20174
20180
Total374