*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197210
19734
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
198421
198516
198619
198718
198817
198918
199011
199112
19926
19930
19940
19950
19961
19970
19980
199916
200034
20012
20021
20031
20042
20050
20061
20073
20080
20090
20100
20112
20122
20133
20143
20151
20161
20175
20180
20190
Total230