A drug, originally priced at 20 yuan per bottle, is now 16 yuan per bottle. How much will the price of this drug be reduced?
一种药品，原来每瓶售价20元，现在每瓶16元，这种药品降价百分之几？
<gadget id="calculator">20 - 16</gadget>
<output>4</output>

<gadget id="calculator">4 / 20</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>