Year ended December 31 | |||||
2015 | 2016 (1) | 2017 (1) | |||
Risk-free interest rate | 1.6% | N/A | N/A | ||
Expected volatility of the market price of our shares | 35% | N/A | N/A | ||
Expected option life (in years) | 5.5 | N/A | N/A | ||
Weighted average fair value of options granted | $4.68 | N/A | N/A |
(1) | No stock options were granted in 2016 or 2017. |