Something

<?php
$result = db_query("select message, count(message) as count from watchdog where type = 'search' and uid = 0 group by message order by count desc limit 300");
print '<div class="column-left"><h2>Anonymous users</h2><ul>';
while ($s = db_fetch_object($result)) {
  preg_match('!<em>(.*?)</em>!', $s->message, $matches);
  print '<li>'. $matches[1] .' ('. $s->count .')</li>';
}
print '</ul></div>';

$result = db_query("select message, count(message) as count from watchdog where type = 'search' and uid != 0 group by message order by count desc limit 300");
print '<div class="column-right"><h2>Authenticated users</h2><ul>';
while ($s = db_fetch_object($result)) {
  preg_match('!<em>(.*?)</em>!', $s->message, $matches);
  print '<li>'. $matches[1] .' ('. $s->count .')</li>';
}
print '</ul></div>';
?>