Table:
|  |  | Year Ended March 31, |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
| Service costs | $1.5 | $2.2 | $1.4 |
| Interest costs | 1.1 | 1.0 | 1.0 |
| Amortization of actuarial loss | 0.4 | 0.8 | — |
| Settlements | — | — | 0.5 |
| Net pension period cost | $3.0 | $4.0 | $2.9 |
Paragraphs:
Note 15. Employee Benefit Plans
Defined Benefit Plans
The Company has defined benefit pension plans that cover certain French and German employees. Most of these defined pension plans, which were acquired in the Atmel and Microsemi acquisitions, are unfunded. Plan benefits are provided in accordance with local statutory requirements. Benefits are based on years of service and employee compensation levels. Pension liabilities and charges are based upon various assumptions, updated annually, including discount rates, future salary increases, employee turnover, and mortality rates. The Company’s French pension plan provides for termination benefits paid to covered French employees only at retirement, and consists of approximately one to five months of salary. The Company's German pension plan provides for defined benefit payouts for covered German employees following retirement.
The aggregate net pension expense relating to these two plans is as follows (in millions):
Interest costs and amortization of actuarial losses are recorded in the other (loss) income, net line item in the statements of income.
Question:
What was the percentage change in the net pension period cost between 2018 and 2019?
Answer: (3.0-4.0)/4.0 = -25