*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19728
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19831
19841
19851
19866
198724
198823
198922
199043
199172
199223
199347
199412
199528
19965
19979
19981
199915
20006
20012
20029
20039
20041
200530
20066
20070
20080
20092
20102
201116
20127
20135
20144
20157
20162
20173
201890
20190
Total543