"type" "yearbuilt" "period" "service" "incidents"
A "1960-64" "1960-74"   127  0
A "1960-64" "1975-79"    63  0
A "1965-69" "1960-74"  1095  3
A "1965-69" "1975-79"  1095  4
A "1970-74" "1960-74"  1512  6
A "1970-74" "1975-79"  3353 18
A "1975-79" "1960-74"     0  0
A "1975-79" "1975-79"  2244 11
B "1960-64" "1960-74" 44882 39
B "1960-64" "1975-79" 17176 29
B "1965-69" "1960-74" 28609 58
B "1965-69" "1975-79" 20370 53
B "1970-74" "1960-74"  7064 12
B "1970-74" "1975-79" 13099 44
B "1975-79" "1960-74"     0  0
B "1975-79" "1975-79"  7117 18
C "1960-64" "1960-74"  1179  1
C "1960-64" "1975-79"   552  1
C "1965-69" "1960-74"   781  0
C "1965-69" "1975-79"   676  1
C "1970-74" "1960-74"   783  6
C "1970-74" "1975-79"  1948  2
C "1975-79" "1960-74"     0  0
C "1975-79" "1975-79"   274  1
D "1960-64" "1960-74"   251  0
D "1960-64" "1975-79"   105  0
D "1965-69" "1960-74"   288  0
D "1965-69" "1975-79"   192  0
D "1970-74" "1960-74"   349  2
D "1970-74" "1975-79"  1208 11
D "1975-79" "1960-74"     0  0
D "1975-79" "1975-79"  2051  4
E "1960-64" "1960-74"    45  0
E "1960-64" "1975-79"     0  0
E "1965-69" "1960-74"   789  7
E "1965-69" "1975-79"   437  7
E "1970-74" "1960-74"  1157  5
E "1970-74" "1975-79"  2161 12
E "1975-79" "1960-74"     0  0
E "1975-79" "1975-79"   542  1