Code:
on *:join:#chan,#otherchan:{
  if ($nick(#,0) > $($+(%,peak.,#,.,$network),2)) || (!$($+(%,peak.,#,.,$network),2)) {
    set $+(%,peak.,#,.,$network) $nick(#,0) $ctime
    echo # There is now a new channel record of $nick(#,0) users!
  }
}
on *:text:!peak:#chan,#otherchan:{
  tokenize 32 $($+(%,peak.,#,.,$network),2)
  if ($0) {
    msg # On $date($2,mmmm dd yyyy) ( $+ $duration($calc($ctime - $2),2) ago $+ ) there were $1 $&
      users (thats $round($calc(100 - $nick(#,0) / $1 * 100),0) $+ % more than now) in # $+ !
  }
}