The fair value of each option was estimated on the date of grant using the Black-Scholes-Merton option-pricing formula, with the following weighted average assumptions: Table of Contents The expected dividend yield used for 2019 was based on the Company's historical dividend yield. The expected volatility of the price of CRD-A was based on historical realized volatility. The risk-free interest rate was based on the U.S. Treasury Daily Yield Curve Rate on the grant date, with a term equal to the expected term used in the pricing formula. The expected term of the option took into account both the contractual term of the option and the effects of expected exercise behavior. Performance share grants are from time to time made to certain key employees of the Company. Such grants entitle employees to earn shares of CRD-A upon the achievement of certain individual and/or corporate objectives. Grants of performance shares are made at the discretion of the Company's Board of Directors, or the Board's Compensation Committee, and are subject to graded or cliff vesting over three-year periods. Shares are not issued until the vesting requirements have been met. Dividends are not paid or accrued on unvested/unissued shares. The grant-date fair value of a performance share grant is based on the market value of CRD-A on the date of grant, reduced for the present value of any dividends expected to be paid on CRD-A prior to the vesting of the award. Compensation expense for each award is recognized ratably from the grant date to the vesting date for each tranche. A summary of the status of the Company's nonvested performance shares as of December 31, 2019, 2018, and 2017, and changes during each year, is presented below: Performance-Based Stock Grants The total fair value of the performance shares that vested in 2019, 2018, and 2017 was $1,823,000, $2,662,000, and $3,597,000, respectively. Compensation expense recognized for all performance shares totaled $1,082,000, $3,307,000, and $3,796,000 for the years ended December 31, 2019, 2018 and 2017, respectively. Compensation cost for these awards is net of estimated or actual award forfeitures. Certain performance awards vest ratably over three years, without cumulative earnings per share targets. As of December 31, 2019, there was an estimated $2,212,000 of unearned compensation cost for nonvested performance shares. This unearned compensation cost is expected to be fully recognized by the end of 2021. Shares Weighted-Average Grant- Date Fair Value Nonvested at December 31, 2016 806,881 $6.17 Granted 930,295 7.54 Vested (668,649) 5.38 Forfeited or unearned (184,185 ) 5.85 Nonvested at December 31, 2017 884,342 7.05 Granted 751,128 7.43 Vested (445,311) 5.98 Forfeited or unearned (201,322 ) 7.54 Nonvested at December 31, 2018 988,837 8.07 Granted 626,776 8.87 Vested (214,824) 8.49 Forfeited or unearned (427,010 ) 8.34 Nonvested at December 31, 2019 973,779 $8.38 2019 2018 Expected dividend yield 3.80 % 3.50 % Expected volatility 36.73% 42.67% Risk-free interest rate 2.56 % 2.75 % Expected term of options 7 years 7 years 92