*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197218
19734
19740
19750
19760
19770
19780
19790
19802
19810
19820
19830
198424
198518
198613
198759
1988144
198938
1990154
1991146
199295
199357
19946
199524
19961
19971
199815
199936
200055
200135
200211
20034
200439
200559
200610
20071
200810
20099
20103
20117
201213
20139
20146
20153
201615
20177
20181
Total1152