Dumb question about the digest topic list

[Chet Ensign <Chet_Ensign%LDS -at- NOTES -dot- WORLDCOM -dot- COM>]

I subscribe to TECHWR-L in digest form so each day I get one big mail message
that begins with a topic listing that looks like this:

                           There are 50 messages totalling 2209 lines in this
issue.

                            Topics of the day:

                            1. Contract writing (3)
                            2. SGML and tech. writing courses
                            3. HTML Development Tools

Can anyone tell me what the numbers in parentheses mean? They are not a part of
the subject line itself.

Thanks,

/chet