The following table summarizes how the impact on the defined benefit obligation as at December 31, 2017 and 2016 would have increased or decreased as a result of the change in the respective assumptions by one percent.
| Pension | Other | |||||||||||||||
| As at December 31, 2017 | 1% increase | 1% decrease | 1% increase | 1% decrease | ||||||||||||
| Discount rate | $ | (42,092 | ) | $ | 53,148 | $ | (2,786 | ) | $ | 3,588 | ||||||
| Future salary growth | $ | 7,988 | $ | (7,457 | ) | N/A | N/A | |||||||||
| Medical and dental trend rates | N/A | N/A | $ | 2,165 | $ | (1,663 | ) | |||||||||
| Pension | Other | |||||||||||||||
| As at December 31, 2016 | 1% increase | 1% decrease | 1% increase | 1% decrease | ||||||||||||
| Discount rate | $ | (37,649 | ) | $ | 47,853 | $ | (2,618 | ) | $ | 3,345 | ||||||
| Future salary growth | $ | 8,028 | $ | (7,076 | ) | N/A | N/A | |||||||||
| Medical and dental trend rates | N/A | N/A | $ | 1,856 | $ | (1,444 | ) | |||||||||