Random_Walk has given a good explanation.
However, maybe the following line could help clear the that line a bit.
print $1,$/ if m{\s+?(\d+?)\/total$};
The above line shows clearly that after "total", what you have is "$" that indicate the end of the string and not "$/". The / that follows "$" is the second "slash" of the match operator i.e

m//
  ^ This one
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In addition to all that, using the module "YAPE::Regex::Explain" the regular expression matches could be explain as thus:

The regular expression:

(?-imsx:\s+?(\d+?)/total$)

matches as follows:
  
NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  \s+?                     whitespace (\n, \r, \t, \f, and " ") (1 or
                           more times (matching the least amount
                           possible))
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    \d+?                     digits (0-9) (1 or more times (matching
                             the least amount possible))
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
  /total                   '/total'
----------------------------------------------------------------------
  $                        before an optional \n, and the end of the
                           string
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------
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