pre_text: five-year performance comparison 2013 the following graph provides an indicator of cumulative total shareholder returns for the corporation as compared to the peer group index ( described above ) , the dow jones , and the s&p 500 . the graph assumes that the value of the investment in the common stock of union pacific corporation and each index was $ 100 on december 31 , 2002 , and that all dividends were reinvested . comparison of five-year cumulative return 2002 2003 2004 2005 2006 2007 upc s&p 500 peer group dj trans purchases of equity securities 2013 during 2007 , we repurchased 13266070 shares of our common stock at an average price of $ 115.66 . during the first nine months of 2007 , we repurchased 10639916 shares of our common stock at an average price per share of $ 112.68 . the following table presents common stock repurchases during each month for the fourth quarter of 2007 : period number of shares purchased average paid per total number of shares purchased as part of a publicly announced plan or program maximum number of shares that may yet be purchased under the plan or program .
post_text: [a] total number of shares purchased during the quarter includes 228354 shares delivered or attested to upc by employees to pay stock option exercise prices , satisfy excess tax withholding obligations for stock option exercises or vesting of retention units , and pay withholding obligations for vesting of retention shares . [b] on january 30 , 2007 , our board of directors authorized us to repurchase up to 20 million shares of our common stock through december 31 , 2009 . we may make these repurchases on the open market or through other transactions . our management has sole discretion with respect to determining the timing and amount of these transactions. .
table: <i>Period</i> <i>TotalNumber ofSharesPurchased[a]</i> <i>AveragePricePaid perShare</i> <i>Total Number of SharesPurchased as Part of aPublicly AnnouncedPlan orProgram</i> <i>Maximum Number ofShares That May YetBe Purchased Underthe Plan orProgram[b]</i>
table: Oct. 1 through Oct. 31 99,782 $ 128.78 - 9,774,279
table: Nov. 1 through Nov. 30 540,294 124.70 528,000 9,246,279
table: Dec. 1 through Dec. 31 1,986,078 128.53 1,869,800 7,376,479
table: Total 2,626,154 $ 127.75 2,397,800 N/A
question: Analyse this data from a financial earnings document. what the percent of the total number of shares purchased in the fourth quarter of 2007 that was attested to upc by employees to pay stock option exercise prices