Run this $GITHUB_HOST/$owner/$repo/graphs/contributors

bookmarklet

javascript:var%20$additions,$averages,$changes,$cmeta,$commits,$contributors,$deletions,$people,$person,createAverageChangesPerCommit,name,parseCommaSeparatedNumeral,person,totalCommits,_i,_len,_ref;parseCommaSeparatedNumeral=function(csn)%7Breturn%20parseInt(csn.replace(/,/,%22%22))%7D;createAverageChangesPerCommit=function($changes,commitCount)%7Bvar%20$averageNode,$lpc,averageLines,changedLines;changedLines=parseCommaSeparatedNumeral($changes.text());averageLines=changedLines/commitCount;$lpc=$(document.createElement(%22abbr%22)).attr(%7Btitle:%22lines%20per%20commit%22%7D).text(%22lpc%22);$averageNode=$(document.createElement(%22span%22)).css(%7Bcolor:$changes.css(%22color%22)%7D).text(%22%22+Math.round(averageLines)+%22%20%22).append($lpc);return%20$(document.createElement(%22span%22)).text(%22%20/%20%22).append($averageNode)%7D;$contributors=$(%22%23contributors%22);$people=$contributors.find(%22.person%22);_ref=$people.get();for(_i=0,_len=_ref.length;_i%3C_len;_i++)%7Bperson=_ref[_i];$person=$(person);$commits=$person.find(%22.cmt%22);$additions=$person.find(%22.a%22);$deletions=$person.find(%22.d%22);$cmeta=$person.find(%22.cmeta%22);name=$person.find(%22.aname%22).text();totalCommits=parseCommaSeparatedNumeral($commits.text());$averages=function()%7Bvar%20_j,_len1,_ref1,_results;_ref1=[$additions,$deletions];_results=[];for(_j=0,_len1=_ref1.length;_j%3C_len1;_j++)%7B$changes=_ref1[_j];_results.push(createAverageChangesPerCommit($changes,totalCommits))%7Dreturn%20_results%7D();$cmeta.append($averages)%7D;void(0)

linesPerCommit.coffee

parseCommaSeparatedNumeral = (csn) ->
  parseInt(csn.replace(/,/, ''))

createAverageChangesPerCommit = ($changes, commitCount) ->
  changedLines = parseCommaSeparatedNumeral($changes.text())
  averageLines = changedLines / commitCount
  $lpc = $(document.createElement('abbr')).attr(title: 'lines per commit').text('lpc')
  $averageNode = $(document.createElement('span')).css(color: $changes.css('color')).text("#{Math.round(averageLines)} ").append($lpc)
  $(document.createElement('span')).text(' / ').append($averageNode)

$contributors = $('#contributors')
$people = $contributors.find('.person')

for person in $people.get()
  $person    = $(person)
  $commits   = $person.find('.cmt')
  $additions = $person.find('.a')
  $deletions = $person.find('.d')
  $cmeta     = $person.find('.cmeta')

  name = $person.find('.aname').text()
  totalCommits = parseCommaSeparatedNumeral($commits.text())

  $averages =
    createAverageChangesPerCommit($changes, totalCommits) for $changes in [$additions, $deletions]

  $cmeta.append($averages)

linesPerCommit.js

var $additions, $averages, $changes, $cmeta, $commits, $contributors, $deletions, $people, $person, createAverageChangesPerCommit, name, parseCommaSeparatedNumeral, person, totalCommits, _i, _len, _ref;

parseCommaSeparatedNumeral = function(csn) {
  return parseInt(csn.replace(/,/, ''));
};

createAverageChangesPerCommit = function($changes, commitCount) {
  var $averageNode, $lpc, averageLines, changedLines;
  changedLines = parseCommaSeparatedNumeral($changes.text());
  averageLines = changedLines / commitCount;
  $lpc = $(document.createElement('abbr')).attr({
    title: 'lines per commit'
  }).text('lpc');
  $averageNode = $(document.createElement('span')).css({
    color: $changes.css('color')
  }).text("" + (Math.round(averageLines)) + " ").append($lpc);
  return $(document.createElement('span')).text(' / ').append($averageNode);
};

$contributors = $('#contributors');

$people = $contributors.find('.person');

_ref = $people.get();
for (_i = 0, _len = _ref.length; _i < _len; _i++) {
  person = _ref[_i];
  $person = $(person);
  $commits = $person.find('.cmt');
  $additions = $person.find('.a');
  $deletions = $person.find('.d');
  $cmeta = $person.find('.cmeta');
  name = $person.find('.aname').text();
  totalCommits = parseCommaSeparatedNumeral($commits.text());
  $averages = (function() {
    var _j, _len1, _ref1, _results;
    _ref1 = [$additions, $deletions];
    _results = [];
    for (_j = 0, _len1 = _ref1.length; _j < _len1; _j++) {
      $changes = _ref1[_j];
      _results.push(createAverageChangesPerCommit($changes, totalCommits));
    }
    return _results;
  })();
  $cmeta.append($averages);
}

See example: