*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19741
19750
19760
19770
19780
19790
19802
19810
19820
19830
19840
19852
19860
198716
19889
19896
19900
199135
19921
199322
199411
199519
19966
199710
19981
19996
200016
20016
20021
20038
20046
20053
20068
200718
200829
200915
201040
201126
201213
201316
201411
201512
201629
201730
20186
201912
20207
20211
20223
20232
20243
Total468