| | | | Pension Plans |
| | | | December 31, | | May 31, |
| | | | 2013 | | 2013 | | 2012 | | 2011 |
| | Discount rate | | 4.75% | | 4.25% | | 4.44% | | 5.13% |
| | Expected return on plan assets | | 6.15% | | 6.13% | | 6.29% | | 6.87% |
| | Rate of compensation increase | | 3.50% | | 4.00% | | 4.00% | | 4.00% |
Weighted-average assumptions used to determine net benefit cost were as follows:
| | | | Pension Plans |
| | | | December 31, | | May 31, |
| | | | 2013 | | 2013 | | 2012 | | 2011 |
| | Discount rate | | 4.25% | | 4.44% | | 5.13% | | 5.61% |
| | Expected return on plan assets | | 6.13% | | 6.29% | | 6.87% | | 6.92% |
| | Rate of compensation increase | | 4.00% | | 4.00% | | 4.00% | | 4.00% |
us-gaap:ScheduleOfAssumptionsUsedTableTextBlock