*Excludes Observations that spanned multiple years

Pre 19707
19700
19711
19720
19730
19740
19750
19761
19770
19781
19790
19802
19811
19821
19834
19841
19851
198658
198719
198840
198912
199011
199134
199232
199351
199434
199592
199630
199771
199840
199931
200039
200123
200226
20034
200466
200571
200613
200720
200820
200922
201033
201128
20120
20132
20143
20152
201628
20173
20180
Total978