Offhand, I'd say this calls for //g.

my @counts; # since there are only 10 possible values, all
            # digits, why use a hash?
while($largeStr=~/Tel: 06(\d)/g) 
{
    $counts[$1]++
}
[download]

I removed the "+" from after the \d, since you really only expect one digit for your extensions, right?

After the loop is done, the @counts array should have the answers you're looking for.
--
Mike

Edit: Wow, foreach doesn't work, but while does. Wierd...