2013 | 2012 | 2011 | ||||
Risk-free interest rate | 1.0% - 1.6% | 0.7% - 0.9% | 0.9% - 2.3% | |||
Expected volatility | 41.0% - 43.0% | 43.2% - 44.0% | 44.3% - 45.1% | |||
Expected dividend yield | 1.4% - 1.6% | 1.2% - 1.7% | 1.0% - 1.4% | |||
Forfeiture rate | 5.0% | 5.0% | 5.0% | |||
Expected life in years | 5.3 | 5.3 - 5.6 | 4.9 - 5.0 |