According to the statistics of the three classes of the sixth grade in a certain elementary school, there are 75 books in the first class of six years, 90 books in the second class of six years, and 155 books in the third class of six years. What percentage is more in the second class of six years than in the first class of six years?
某小学统计六年级三个班拥有图书情况，六年一班75本，六年二班90本，六年三班155本，六年二班比六年一班多百分之几？
<gadget id="calculator">90 - 75</gadget>
<output>15</output>

<gadget id="calculator">15 / 75</gadget>
<output>1/5 = around 0.2</output>

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