In April 2007, my country's train speed was increased for the sixth time, and the train speed on a certain main line increased from an average of 160 kilometers per hour to an average of 200 kilometers per hour. By what percentage has the train speed increased?
2007年4月我国火车第六次提速，某火车干线上火车速度从平均每小时160千米提高到平均每小时200千米．火车速度提高了百分之几？
<gadget id="calculator">200 - 160</gadget>
<output>40</output>

<gadget id="calculator">40 / 160</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>