*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
19916
19920
19937
19943
19950
19961
19971
19981
19991
200021
200110
200238
200330
200420
200523
200634
200735
200821
200916
201051
201132
201219
201323
20140
20150
20160
20170
Total393