private function _writeAutoFilterInfo(){
		$record	  = 0x009D;						// Record identifier
		$length	  = 0x0002;						// Bytes to follow

		$rangeBounds = PHPExcel_Cell::rangeBoundaries($this->_phpSheet->getAutoFilter()->getRange());
		$iNumFilters = 1 + $rangeBounds[1][0] - $rangeBounds[0][0];

		$header   = pack("vv", $record, $length);
		$data     = pack("v",  $iNumFilters);
		$this->_append($header . $data);
	}