*Excludes Observations that spanned multiple years

Pre 19700
19701
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19821
19830
19840
198514
19860
198735
198857
198915
199064
1991108
199230
199339
19945
199527
199612
19978
19982
19994
20005
20010
20025
20031
20043
20052
20061
20071
20089
20092
20101
20113
20121
20131
20143
20153
20169
20171
20181
20190
20200
Total474