Xiao Ming's father bought 40,000 yuan of stock and paid 80 yuan in stamp duty. What is the rate of stamp duty?
小明的爸爸购买了40000元的股票，缴纳印花税80元，印花税的税率是多少．
<gadget id="calculator">80 / 80_000</gadget>
<output>1/1_000 = around 0.001</output>

<result>1/1_000 = around 0.001</result>