Mobile phone call charges have been continuously reduced. A certain mobile phone call charge used to be 0.44 yuan per minute, but now it is 0.22 yuan per minute. How much is the reduction?
手机通话费不断下调，某项手机通话费原来每分钟0.44元，现在每分钟0.22元，下调了百分之几？
<gadget id="calculator">0.44 - 0.22</gadget>
<output>0.22</output>

<gadget id="calculator">0.22 / 0.44</gadget>
<output>0.5</output>

<result>0.5</result>