*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970300104
1970000000
1971300003
1972300003
1973100001
1974100102
1975300003
1976500005
1977200002
1978400004
1979300104
1980000000
1981200103
1982500005
1983500106
1984300003
1985600309
198611002013
19879102012
1988500409
19899001010
199013004017
1991300609
19927007014
199310005015
199411005016
19954006010
199660015021
19978005013
19989006015
1999400206
20007004011
20016006012
200230010013
20035008013
200430012015
20058004012
2006510309
20075009014
200840010014
200911010012
2010200406
201110010011
2012200305
2013100405
2014100001
2015000101
2016000000
2017000000
2018000000
Total212301760391