*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19840
19850
19865
19873
198810
198921
199014
199111
199228
199354
199444
199584
199619
199747
199860
199925
200027
200117
200217
20039
200411
200569
20066
200718
200812
200915
20101
20112
20120
20130
20141
20150
20160
20170
Total631