as of 30 september 2018 , there was $ .1 of unrecognized compensation cost related to restricted stock awards . the cost is expected to be recognized over a weighted average period of 0.5 years . the total fair value of restricted stock vested during fiscal years 2018 , 2017 , and 2016 was $ 2.2 , $ 4.1 , and $ 4.3 , respectively . as discussed in note 3 , discontinued operations , air products completed the spin-off of versum on 1 october 2016 . in connection with the spin-off , the company adjusted the number of deferred stock units and stock options pursuant to existing anti-dilution provisions in the ltip to preserve the intrinsic value of the awards immediately before and after the separation . the outstanding awards will continue to vest over the original vesting period defined at the grant date . outstanding awards at the time of spin-off were primarily converted into awards of the holders' employer following the separation . stock awards held upon separation were adjusted based upon the conversion ratio of air products' new york stock exchange ( 201cnyse 201d ) volume weighted-average closing stock price on 30 september 2016 ( $ 150.35 ) to the nyse volume weighted-average opening stock price on 3 october 2016 ( $ 140.38 ) , or 1.071 . the adjustment to the awards did not result in incremental fair value , and no incremental compensation expense was recorded related to the conversion of these awards. .
compensation cost is generally recognized over the stated vesting period consistent with the terms of the arrangement ( i.e. , either on a straight-line or graded-vesting basis ) . expense recognition is accelerated for retirement-eligible individuals who would meet the requirements for vesting of awards upon their retirement . as of 30 september 2018 , there was no unrecognized compensation cost as all stock option awards were fully vested . cash received from option exercises during fiscal year 2018 was $ 76.2 . the total tax benefit realized from stock option exercises in fiscal year 2018 was $ 25.8 , of which $ 19.0 was the excess tax benefit . restricted stock the grant-date fair value of restricted stock is estimated on the date of grant based on the closing price of the stock , and compensation cost is generally amortized to expense on a straight-line basis over the vesting period during which employees perform related services . expense recognition is accelerated for retirement-eligible individuals who would meet the requirements for vesting of awards upon their retirement . we have elected to account for forfeitures as they occur , rather than to estimate them . forfeitures have not been significant historically . we have issued shares of restricted stock to certain officers . participants are entitled to cash dividends and to vote their respective shares . restrictions on shares lift in one to four years or upon the earlier of retirement , death , or disability . the shares are nontransferable while subject to forfeiture . a summary of restricted stock activity is presented below : restricted stock shares ( 000 ) weighted average grant- date fair value .
what was the decrease observed in the total fair value of restricted stock that vested during 2017 and 2018?
the total fair value of restricted stock vested during fiscal years 2018 , 2017 , and 2016 was $ 2.2 , $ 4.1 , and $ 4.3 , respectively .
restricted stock shares ( 000 ) weighted averagegrant-date fair value
outstanding at 30 september 2017 56 $ 135.74
vested ( 14 ) 121.90
outstanding at 30 september 2018 42 $ 140.28