Indicate by letter whether each of the events listed below increases (I), decreases (D), or has no effect (N) on an employer's periodic pension expense in the year the event occurs.
Events

_____1. Interest cost.
_____2. Amortization of prior service cost-AOCI.
_____3. Excess of the expected return on plan assets over the actual return.
_____4. Expected return on plan assets.
_____5. A plan amendment that increases benefits is made retroactive to prior years.
_____6. Actuary's estimate of the PBO is increased.
_____7. Cash contributions to the pension fund by the employer.
_____8. Benefits are paid to retired employees.
_____9. Service cost.
_____10. Excess of the actual return on plan assets over the expected return.
_____11. Amortization of net loss-AOCI.
_____12. Amortization of net gain-AOCI.