*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197214
19732
19740
19750
19760
19771
19780
19790
19800
19810
19820
19830
198439
198532
198646
198751
198840
198926
199041
199155
199228
19933
19943
19951
19963
19977
19981
1999120
2000128
200120
20027
20031
20042
20052
20063
20071
20084
20091
20102
201110
20125
20136
20142
20153
201614
201710
20181
Total735