The national debt of 3,000 yuan has a two-year period, and 3,541.2 yuan will be returned after maturity. What is the annual interest rate of the national debt?
3000元的国债两年期，到期后取回3541.2元，求国债的年利率是多少．
<gadget id="calculator">3_541.2 - 3_000</gadget>
<output>541.2</output>

<gadget id="calculator">541.2 / 3_000 / 2</gadget>
<output>0.0902</output>

<result>0.0902</result>