There were 12,000 books in the school library, and 5,000 were purchased in the first half of this year, and another 4,000 were purchased in the second half of the year. How many percent has the volume of books in the library increased now?
学校图书室原有图书1.2万册，今年上半年购进了5000册，下半年又购进了4000册．现在图书室的图书量比原来增加了百分之几？
<gadget id="calculator">5_000 + 4_000</gadget>
<output>9_000</output>

<gadget id="calculator">1.2 * 10_000</gadget>
<output>12_000</output>

<gadget id="calculator">9_000 / 12_000</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>