*Excludes Observations that spanned multiple years

Pre 19703
19700
19710
19720
19730
19740
19751
19760
19770
19781
19790
19801
19811
19820
198310
19840
19850
19866
19871
19887
19898
199014
19912
199226
199321
199417
199517
19965
19979
199822
199910
20004
200113
20021
200310
200461
200522
20063
20074
20089
20093
201031
201164
20120
20133
201414
201518
201620
201751
20180
Total513