A milk factory produces 5.5 million tons of milk this year, an increase of 1.1 million tons over last year. What percentage is the increase this year compared to last year?
某牛奶厂今年年产牛奶550万吨，比去年增加了110万吨，今年比去年提高了百分之几？
<gadget id="calculator">550 - 110</gadget>
<output>440</output>

<gadget id="calculator">110 / 440</gadget>
<output>1/4 = around 0.25</output>

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