*Excludes Observations that spanned multiple years

Pre 19701
19700
19710
19723
19731
19740
19750
19760
19770
19780
19790
19800
19810
19820
19831
19840
19850
198616
19878
19881
19896
199026
199156
19928
199341
19943
199526
199613
19977
19981
19996
20002
20010
20020
20030
20040
20052
20060
20070
20087
20090
201028
201159
20120
20130
20141
20150
20161
20172
20180
Total326