*Excludes Observations that spanned multiple years

Pre 19700
19700
19711
19720
19730
19740
19750
19760
19770
19781
19791
19800
19810
19820
19830
19841
19853
19860
19870
19880
198911
19904
199117
199210
199320
19943
199511
199613
199725
19983
199915
200010
20014
20021
200320
200418
200520
20067
200729
20089
200921
201031
201128
201230
201342
201415
201531
201635
201745
201817
20199
20204
20213
20227
20232
20249
Total586