earnings in 2009 这里的earnings 指的什么

问题如下：

(2) Compared to the assumptions Stereo Warehouse used to compute its periodic pension cost in 2008, earnings in 2009 were most favorably affected by the change in the:

选项：

discount rate.

estimated future salary increases.

expected long-term rate of return on plan assets.

解释：

In 2009, the three relevant assumptions were lower than in 2008. Lower expected salary increases reduce the service cost component of the periodic pension cost. A lower discount rate will increase the defined benefit obligation and increase the interest cost component of the periodic pension cost (the increase in the obligation will, in most cases, more than offset the decrease in the discount rate). Reducing the expected return on plan assets typically increases the periodic pension cost.