This is an old stats script, only been tested on mIRC 6.31, no promise it works well on others.
Its simple and just keeps track of several stats.

    alias stats {
      window -adf @stats 0 500 340 550
      aline @stats mIRC Statistics!
      aline @stats ----------------
      aline @stats mIRC Version: $version
      aline @stats mIRC Uptime: $uptime(mirc,1)
      aline @stats System Uptime: $uptime(system,1)
      aline @stats System Time: $fulldate
      aline @stats IP: $ip
      aline @stats Connected to server: $server
      aline @stats ServerIP: $serverip
      aline @stats Open Channels: $chan(0)
      aline @stats Usermodes: $usermode
      aline @stats Total Networks: $scon(0)
      aline @stats ----------------
      aline @stats UserTotal list:
      aline @stats OPs: $bytes($readini(maindb.ini, total, ops), b) DEOPs: $bytes($readini(maindb.ini, total, deops), b)
      aline @stats Voices: $bytes($readini(maindb.ini, total, voices), b) Devoices: $bytes($readini(maindb.ini, total, devoices), b)
      aline @stats Kicks performed: $bytes($readini(maindb.ini, total, kicks), b) Kicks on me: $bytes($readini(maindb.ini, total, kickmes), b)
      aline @stats Joins: $bytes($readini(maindb.ini, total, joins), b) Parts: $bytes($readini(maindb.ini, total, parts), b)
      aline @stats Connects: $bytes($readini(maindb.ini, total, connects), b) Disconnects: $bytes($readini(maindb.ini, total, disconnects), b)
      aline @stats Starts: $bytes($readini(maindb.ini, total, starts), b)
      aline @stats Nickchanges: $bytes($readini(maindb.ini, total, nickc), b)
      aline @stats Invites: $bytes($readini(maindb.ini, total, invites), b)
      aline @stats Tabcompletions: $bytes($readini(maindb.ini, total, tabcomps), b)
      aline @stats Words: $bytes($readini(maindb.ini, total, swords), b)
      aline @stats Letters: $bytes($readini(maindb.ini, total, stext), b)
      aline @stats Lines: $bytes($readini(maindb.ini, total, slines), b)
    }
    on *:KICK:#:{
      if ($knick == $me) {
        writeini -n maindb.ini total kickmes $calc($readini(maindb.ini, total, kickmes) + 1)
      }
    }
    on *:NICK:{
      if ($nick == $me) {
        writeini -n maindb.ini total nickc $calc($readini(maindb.ini, total, nickc) + 1)
      }
    }
    on *:INVITE:#:{
      writeini -n maindb.ini total invites $calc($readini(maindb.ini, total, invites) + 1)
    }
    on *:TABCOMP:*:{
      writeini -n maindb.ini total tabcomps $calc($readini(maindb.ini, total, tabcomps) + 1)
    }
    on *:START:{
      writeini -n maindb.ini total starts $calc($readini(maindb.ini, total, starts) + 1)
    }
    on *:CONNECT:{
      writeini -n maindb.ini total connects $calc($readini(maindb.ini, total, connects) + 1)
    }
    on *:DISCONNECT:{
      writeini -n maindb.ini total disconnects $calc($readini(maindb.ini, total, disconnects) + 1)
    }
    on *:JOIN:*:{
      if ($nick == $me) {
        writeini -n maindb.ini total joins $calc($readini(maindb.ini, total, joins) + 1)
      }
    }
    on *:INPUT:*:{
      if ($1 != $null) {
        writeini -n maindb.ini total swords $calc($readini(maindb.ini, total , swords) + $0)
        writeini -n maindb.ini total stext $calc($readini(maindb.ini, total , stext) + $count($1-, a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,$chr(44),$chr(45),$chr(46),$chr(34),$chr(36),$chr(35),$chr(33),$chr(39),$chr(47),$chr(38),$chr(37),$chr(40),$chr(41),$chr(42),$chr(43),$chr(64),$chr(63),$chr(62),$chr(61),$chr(60),$chr(59),$chr(58),$chr(95),$chr(94),$chr(93),$chr(92),$chr(124),$chr(125),$chr(123),$chr(126)))
        writeini -n maindb.ini total slines $calc($readini(maindb.ini, total , slines) + 1)
      }
    }
    on *:PART:*:{
      if ($nick == $me) {
        writeini -n maindb.ini total parts $calc($readini(maindb.ini, total, parts) + 1)
      }
    }
    on *:DEOP:#:{
      if ($opnick == $me) {
        writeini -n maindb.ini total deops $calc($readini(maindb.ini, total, deops) + 1)
      }
    }
    on *:OP:#:{
      if ($opnick == $me) {
        writeini -n maindb.ini total ops $calc($readini(maindb.ini, total, ops) + 1)
      }
    }
    on *:VOICE:#:{
      if ($vnick == $me) {
        writeini -n maindb.ini total voices $calc($readini(maindb.ini, total, voices) + 1)
      }
    }
    on *:DEVOICE:#:{
      if ($vnick == $me) {
        writeini -n maindb.ini total devoices $calc($readini(maindb.ini, total, devoices) + 1)
      }
    }