Key assumptions are as follows: | |||||||||||||||||
Pension Plans | Postretirement Medical Plans | ||||||||||||||||
2013 | 2012 | 2011 | 2013 | 2012 | 2011 | ||||||||||||
Discount rate | 5.00 | % | 3.85 | % | 4.75 | % | 5.00 | % | 3.85 | % | 4.75 | % | |||||
Rate of return on plan assets | 7.50 | % | 7.75 | % | 7.75 | % | 7.50 | % | 7.75 | % | 7.75 | % | |||||
Rate of salary increase | 4.00 | % | 4.00 | % | 4.00 | % | n/a | n/a | n/a | ||||||||
Year 1 increase in cost of benefits | n/a | n/a | n/a | 7.25 | % | 7.50 | % | 8.00 | % | ||||||||
Rate of increase to which the cost of benefits is assumed to decline (the ultimate trend rate) | n/a | n/a | n/a | 4.25 | % | 4.50 | % | 4.50 | % | ||||||||
Year that the rate reaches the ultimate trend rate | n/a | n/a | n/a | 2027 | 2026 | 2025 | |||||||||||