*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970100001
1970100001
1971000000
1972200002
1973200002
1974201003
1975300003
1976801009
1977102014
19789010010
197911050016
1980503008
198120170120
198200100010
1983002002
1984104005
1985103004
198620100012
19877070115
198812080020
198930100114
199053130021
199170170024
199230170121
199332280033
199453350245
199580450053
199673330043
199775370251
199832330745
199963260439
200053440254
2001102430156
200252440253
200332860192
200442460355
200552750183
200685740087
200753790087
200810940095
200918218300203
201018222100241
201113525400272
20120116102164
201300830184
201402340036
201510160118
2016000011
2017001001
Total2235419060352218