Not counting the data section,
i get a score of 128. i'm not counting the data section since anyone golfing will need the input, so it shouldn't be counted. That's my theory at least. Anyway, here's my attempt:
#23456789_123456789_123456789_123456789_123456789_123456789_123456789_
$_=<DATA>;push@_,@+while/_/g;{for$a(0..$#_){substr($_,$_[$a]-1,1
)=$;,$|++if($;=@{[/$a/g]})!=substr$_,$_[$a]-1,1}$|--&&redo}print
__DATA__
The number of 0s in this sentence is _, of 1s is _, of 2s is _, of 3s
+is _, of 4
s is _, of 5s is _, of 6s is _, of 7s is _, of 8s is _, and of 9s is _
+.
On the other hand, here's a much shorter 77 byte solution that's less interesting. It uses the same data section as above. Please note in both cases there should be no "\n"s in the data.
sub{$a=<DATA>;$a=~s,($_.*?)_,$1.pop,efor-1..9;print$a}->(1,1,2,1,1,1,2
+,3,7,1)
enjoy,
jynx