Membuat Dropdown Pilih Bulan & Tahun di PHP

<?php if(isset($_POST["Cari"])){
 $bulan = $_POST['bulan'];
 $tahun = $_POST['tahun'];
$print="modul/penyakit/cetak.php?bln=$bulan&th=$tahun";
}
?>

<form method='post'>
<table  style='width:98%;margin:20px'>
  <tr>
  <td width='10%'>
  <label>Pilih Bulan</label>
  </td>
  <td width='15%'>
  <select name='bulan' id='bulan' class='form-control'>
    <option value='01'<?php if($bulan=="01"){ echo " selected";}?>>Januari</option>
    <option value='02'<?php if($bulan=="02"){ echo " selected";}?>>Februari</option>
    <option value='03'<?php if($bulan=="03"){ echo " selected";}?>>Maret</option>
    <option value='04'<?php if($bulan=="04"){ echo " selected";}?>>April</option>
    <option value='05'<?php if($bulan=="05"){ echo " selected";}?>>Mei</option>
    <option value='06'<?php if($bulan=="06"){ echo " selected";}?>>Juni</option>
    <option value='07'<?php if($bulan=="07"){ echo " selected";}?>>Juli</option>
    <option value='08'<?php if($bulan=="08"){ echo " selected";}?>>Agustus</option>
    <option value='09'<?php if($bulan=="09"){ echo " selected";}?>>September</option>
    <option value='10'<?php if($bulan=="10"){ echo " selected";}?>>Oktober</option>
    <option value='11'<?php if($bulan=="11"){ echo " selected";}?>>November</option>
    <option value='12'<?php if($bulan=="12"){ echo " selected";}?>>Desember</option>
    </select>
  </td>
  <td width='5%'>
    <label> &emsp; Tahun</label>

  </td><td width='15%'>
    <select name='tahun' id='tahun'  class='form-control'>
  <?php  $mulai= date('Y') - 2;
    for($i = $mulai;$i<$mulai + 100;$i++){
    ?>
      <option value='<?php echo $i; ?>'<?php if($i==$tahun){ echo " selected";}?> ><?php echo $i; ?></option>

      <?php
    }
    ?>

    </select>
   </td width='50%'>
   <td>
     &emsp;<input type='submit' name='Cari' value='Proses' class='btn btn-sm btn-success'>

  <a class='btn btn-success btn-sm pull-right' target='_blank' href='<?php echo $print;?>'>
  <i class='glyphicon glyphicon-print'></i> Cetak
</a>
  </td>
  </tr>
  </table>
</form>
<?php

if(isset($_POST["Cari"])){
$act=isset($_GET['act']) ? $_GET['act']:'';
$bulan = $_POST['bulan'];
$tahun = $_POST['tahun'];
echo "