*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19728
19734
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
198481
198513
198636
198734
198872
198915
199011
19918
199213
19930
19940
19950
19961
19970
19980
199937
200066
200121
200213
20036
20041
20052
20064
20072
20084
20091
20101
20111
20123
20135
20144
20155
20165
20172
20180
20190
Total479