pre_text: stock-based compensation 2013 we have several stock-based compensation plans under which employees and non-employee directors receive stock options , nonvested retention shares , and nonvested stock units . we refer to the nonvested shares and stock units collectively as 201cretention awards 201d . we issue treasury shares to cover option exercises and stock unit vestings , while new shares are issued when retention shares vest . we adopted fasb statement no . 123 ( r ) , share-based payment ( fas 123 ( r ) ) , on january 1 , 2006 . fas 123 ( r ) requires us to measure and recognize compensation expense for all stock-based awards made to employees and directors , including stock options . compensation expense is based on the calculated fair value of the awards as measured at the grant date and is expensed ratably over the service period of the awards ( generally the vesting period ) . the fair value of retention awards is the stock price on the date of grant , while the fair value of stock options is determined by using the black-scholes option pricing model . we elected to use the modified prospective transition method as permitted by fas 123 ( r ) and did not restate financial results for prior periods . we did not make an adjustment for the cumulative effect of these estimated forfeitures , as the impact was not material . as a result of the adoption of fas 123 ( r ) , we recognized expense for stock options in 2006 , in addition to retention awards , which were expensed prior to 2006 . stock-based compensation expense for the year ended december 31 , 2006 was $ 22 million , after tax , or $ 0.08 per basic and diluted share . this includes $ 9 million for stock options and $ 13 million for retention awards for 2006 . before taxes , stock-based compensation expense included $ 14 million for stock options and $ 21 million for retention awards for 2006 . we recorded $ 29 million of excess tax benefits as an inflow of financing activities in the consolidated statement of cash flows for the year ended december 31 , 2006 . prior to the adoption of fas 123 ( r ) , we applied the recognition and measurement principles of accounting principles board opinion no . 25 , accounting for stock issued to employees , and related interpretations . no stock- based employee compensation expense related to stock option grants was reflected in net income , as all options granted under those plans had a grant price equal to the market value of our common stock on the date of grant . stock-based compensation expense related to retention shares , stock units , and other incentive plans was reflected in net income . the following table details the effect on net income and earnings per share had compensation expense for all of our stock-based awards , including stock options , been recorded in the years ended december 31 , 2005 and 2004 based on the fair value method under fasb statement no . 123 , accounting for stock-based compensation . pro forma stock-based compensation expense year ended december 31 , millions of dollars , except per share amounts 2005 2004 .
post_text: [a] stock options for executives granted in 2003 and 2002 included a reload feature . this reload feature allowed executives to exercise their options using shares of union pacific corporation common stock that they already owned and obtain a new grant of options in the amount of the shares used for exercise plus any shares withheld for tax purposes . the reload feature of these option grants could only be exercised if the .
table: <i>Pro Forma Stock-Based Compensation Expense</i> Year Ended December 31,
table: <i>Millions of Dollars, Except Per Share Amounts</i> 2005 2004
table: Net income, as reported $1,026 $604
table: Stock-based employee compensation expense, reported in net income, net of tax 13 13
table: Total stock-based employee compensation expense determined under fair value–based method for allawards, net of tax [a] (50) (35)
table: Pro forma net income $989 $582
table: Earnings per share – basic, as reported $3.89 $2.33
table: Earnings per share – basic, pro forma $3.75 $2.25
table: Earnings per share – diluted, as reported $3.85 $2.30
table: Earnings per share – diluted, pro forma $3.71 $2.22
question: Analyse this data from a financial earnings document. what was the percentage of the increase in the basic earnings per share 2013 as reported from 2005 to 2006