*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970001023
1970001001
1971001001
1972000000
1973002002
1974002002
1975001001
1976003003
1977005005
1978003003
1979001001
1980004004
1981005005
1982003003
1983003003
1984004004
1985006006
1986007007
198700100111
198800120012
198900140014
19902570014
199141230028
199200200020
199300190019
199400390039
199501330034
199600300131
199700270027
199800300030
199900300030
200001520053
200112480152
200200520052
200301630266
200403670070
200512540158
20060210400106
20070310900112
20081712800136
20092416500171
20100624700253
20110021601217
2012018770196
20130016200162
20140437400117
201500380038
201600150015
2017006006
Total119920230102143