*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19900
19910
19920
19937
19940
19950
19961
19971
19981
199919
200019
20019
200210
200314
20047
200512
200618
20078
20083
20090
201010
20110
20125
201313
20140
20150
20160
20170
Total157