stock-based awards under the plan stock options 2013 marathon grants stock options under the 2007 plan and previously granted options under the 2003 plan .
marathon 2019s stock options represent the right to purchase shares of common stock at the fair market value of the common stock on the date of grant .
through 2004 , certain stock options were granted under the 2003 plan with a tandem stock appreciation right , which allows the recipient to instead elect to receive cash and/or common stock equal to the excess of the fair market value of shares of common stock , as determined in accordance with the 2003 plan , over the option price of the shares .
in general , stock options granted under the 2007 plan and the 2003 plan vest ratably over a three-year period and have a maximum term of ten years from the date they are granted .
stock appreciation rights 2013 prior to 2005 , marathon granted sars under the 2003 plan .
no stock appreciation rights have been granted under the 2007 plan .
similar to stock options , stock appreciation rights represent the right to receive a payment equal to the excess of the fair market value of shares of common stock on the date the right is exercised over the grant price .
under the 2003 plan , certain sars were granted as stock-settled sars and others were granted in tandem with stock options .
in general , sars granted under the 2003 plan vest ratably over a three-year period and have a maximum term of ten years from the date they are granted .
stock-based performance awards 2013 prior to 2005 , marathon granted stock-based performance awards under the 2003 plan .
no stock-based performance awards have been granted under the 2007 plan .
beginning in 2005 , marathon discontinued granting stock-based performance awards and instead now grants cash-settled performance units to officers .
all stock-based performance awards granted under the 2003 plan have either vested or been forfeited .
as a result , there are no outstanding stock-based performance awards .
restricted stock 2013 marathon grants restricted stock and restricted stock units under the 2007 plan and previously granted such awards under the 2003 plan .
in 2005 , the compensation committee began granting time-based restricted stock to certain u.s.-based officers of marathon and its consolidated subsidiaries as part of their annual long-term incentive package .
the restricted stock awards to officers vest three years from the date of grant , contingent on the recipient 2019s continued employment .
marathon also grants restricted stock to certain non-officer employees and restricted stock units to certain international employees ( 201crestricted stock awards 201d ) , based on their performance within certain guidelines and for retention purposes .
the restricted stock awards to non-officers generally vest in one-third increments over a three-year period , contingent on the recipient 2019s continued employment .
prior to vesting , all restricted stock recipients have the right to vote such stock and receive dividends thereon .
the non-vested shares are not transferable and are held by marathon 2019s transfer agent .
common stock units 2013 marathon maintains an equity compensation program for its non-employee directors under the 2007 plan and previously maintained such a program under the 2003 plan .
all non-employee directors other than the chairman receive annual grants of common stock units , and they are required to hold those units until they leave the board of directors .
when dividends are paid on marathon common stock , directors receive dividend equivalents in the form of additional common stock units .
stock-based compensation expense 2013 total employee stock-based compensation expense was $ 80 million , $ 83 million and $ 111 million in 2007 , 2006 and 2005 .
the total related income tax benefits were $ 29 million , $ 31 million and $ 39 million .
in 2007 and 2006 , cash received upon exercise of stock option awards was $ 27 million and $ 50 million .
tax benefits realized for deductions during 2007 and 2006 that were in excess of the stock-based compensation expense recorded for options exercised and other stock-based awards vested during the period totaled $ 30 million and $ 36 million .
cash settlements of stock option awards totaled $ 1 million and $ 3 million in 2007 and 2006 .
stock option awards granted 2013 during 2007 , 2006 and 2005 , marathon granted stock option awards to both officer and non-officer employees .
the weighted average grant date fair value of these awards was based on the following black-scholes assumptions: .

2007
2006
2005
Weighted average exercise price per share
$60.94
$37.84
$25.14
Expected annual dividends per share
$0.96
$0.80
$0.66
Expected life in years
5.0
5.1
5.5
Expected volatility
27%
28%
28%
Risk-free interest rate
4.1%
5.0%
3.8%
Weighted average grant date fair value of stock option awards granted
$17.24
$10.19
$6.15

.

Question: Analyse this data from a financial earnings document. by how much did the weighted average exercise price per share increase from 2005 to 2007?
Choices:
-1.42403
0.17811
1.42403
0
1.32593
Correct choice index: 2