Financial report context:
the performance units granted to certain executives in fiscal 2014 were based on a one-year performance period . after the compensation committee certified the performance results , 25% ( 25 % ) of the performance units converted to unrestricted shares . the remaining 75% ( 75 % ) converted to restricted shares that vest in equal installments on each of the first three anniversaries of the conversion date . the performance units granted to certain executives during fiscal 2015 were based on a three-year performance period . after the compensation committee certifies the performance results for the three-year period , performance units earned will convert into unrestricted common stock . the compensation committee may set a range of possible performance-based outcomes for performance units . depending on the achievement of the performance measures , the grantee may earn up to 200% ( 200 % ) of the target number of shares . for awards with only performance conditions , we recognize compensation expense over the performance period using the grant date fair value of the award , which is based on the number of shares expected to be earned according to the level of achievement of performance goals . if the number of shares expected to be earned were to change at any time during the performance period , we would make a cumulative adjustment to share-based compensation expense based on the revised number of shares expected to be earned . during fiscal 2015 , certain executives were granted performance units that we refer to as leveraged performance units , or lpus . lpus contain a market condition based on our relative stock price growth over a three-year performance period . the lpus contain a minimum threshold performance which , if not met , would result in no payout . the lpus also contain a maximum award opportunity set as a fixed dollar and fixed number of shares . after the three-year performance period , one-third of any earned units converts to unrestricted common stock . the remaining two-thirds convert to restricted stock that will vest in equal installments on each of the first two anniversaries of the conversion date . we recognize share-based compensation expense based on the grant date fair value of the lpus , as determined by use of a monte carlo model , on a straight-line basis over the requisite service period for each separately vesting portion of the lpu award . total shareholder return units before fiscal 2015 , certain of our executives were granted total shareholder return ( 201ctsr 201d ) units , which are performance-based restricted stock units that are earned based on our total shareholder return over a three-year performance period compared to companies in the s&p 500 . once the performance results are certified , tsr units convert into unrestricted common stock . depending on our performance , the grantee may earn up to 200% ( 200 % ) of the target number of shares . the target number of tsr units for each executive is set by the compensation committee . we recognize share-based compensation expense based on the grant date fair value of the tsr units , as determined by use of a monte carlo model , on a straight-line basis over the vesting period . the following table summarizes the changes in unvested share-based awards for the years ended may 31 , 2015 and 2014 ( shares in thousands ) : shares weighted-average grant-date fair value .

Financial table:
shares: unvested at may 31 2013; weighted-averagegrant-datefair value: 1096; column_3: $ 44
shares: granted; weighted-averagegrant-datefair value: 544; column_3: 47
shares: vested; weighted-averagegrant-datefair value: -643 ( 643 ); column_3: 45
shares: forfeited; weighted-averagegrant-datefair value: -120 ( 120 ); column_3: 45
shares: unvested at may 31 2014; weighted-averagegrant-datefair value: 877; column_3: 45
shares: granted; weighted-averagegrant-datefair value: 477; column_3: 72
shares: vested; weighted-averagegrant-datefair value: -324 ( 324 ); column_3: 46
shares: forfeited; weighted-averagegrant-datefair value: -106 ( 106 ); column_3: 53
shares: unvested at may 31 2015; weighted-averagegrant-datefair value: 924; column_3: $ 58

Additional report context:
global payments inc . | 2015 form 10-k annual report 2013 81 .

Question: what is the net change in the balance of unvested shares from 2013 to 2015?
Answer: -172