*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
19875
198813
198935
199015
199113
199212
19939
19941
19953
19961
19979
19982
19992
20003
20015
20023
20031
20043
20052
20060
20073
20082
20092
20100
20117
20125
20133
20146
20156
20164
20176
20180
Total181