public function getMemPercentCache()
    {
        if ($this->_memCache !== null) {
            if (($this->_memCache > 0) && ($this->_memTotal > 0)) {
                if (($this->_memApplication !== null) && ($this->_memApplication > 0)) {
                    return round(($this->_memCache + $this->_memApplication) / $this->_memTotal * 100) - $this->getMemPercentApplication();
                } else {
                    return round($this->_memCache / $this->_memTotal * 100);
                }
            } else {
                return 0;
            }
        } else {
            return null;
        }
    }