Financial report context:
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Financial table:
2008: weighted average fair value of options granted; 2007: $ 18.47; 2006: $ 33.81; column_4: $ 20.01
2008: expected volatility; 2007: 0.3845; 2006: 0.3677; column_4: 0.3534
2008: dividend yield; 2007: 3.75% ( 3.75 % ); 2006: 0.76% ( 0.76 % ); column_4: 1.00% ( 1.00 % )
2008: expected life of options in years; 2007: 6.0; 2006: 6.0; column_4: 6.3
2008: risk-free interest rate; 2007: 2% ( 2 % ); 2006: 4% ( 4 % ); column_4: 5% ( 5 % )

Additional report context:
the black-scholes option valuation model was developed for use in estimating the fair value of traded options which have no vesting restrictions and are fully transferable . in addition , option valuation models require the input of highly subjective assumptions , including the expected stock price volatility . because the company 2019s employee stock options have characteristics significantly different from those of traded options , and because changes in the subjective input assumptions can materially affect the fair value estimate , in management 2019s opinion , the existing models do not necessarily provide a reliable single measure of the fair value of its employee stock options . the fair value of the rsus was determined based on the market value at the date of grant . the total fair value of awards vested during 2008 , 2007 , and 2006 was $ 35384 , $ 17840 , and $ 9413 , respectively . the total stock based compensation expense calculated using the black-scholes option valuation model in 2008 , 2007 , and 2006 was $ 38872 , $ 22164 , and $ 11913 , respectively.the aggregate intrinsic values of options outstanding and exercisable at december 27 , 2008 were $ 8.2 million and $ 8.2 million , respectively . the aggregate intrinsic value of options exercised during the year ended december 27 , 2008 was $ 0.6 million . aggregate intrinsic value represents the positive difference between the company 2019s closing stock price on the last trading day of the fiscal period , which was $ 19.39 on december 27 , 2008 , and the exercise price multiplied by the number of options exercised . as of december 27 , 2008 , there was $ 141.7 million of total unrecognized compensation cost related to unvested share-based compensation awards granted to employees under the stock compensation plans . that cost is expected to be recognized over a period of five years . employee stock purchase plan the shareholders also adopted an employee stock purchase plan ( espp ) . up to 2000000 shares of common stock have been reserved for the espp . shares will be offered to employees at a price equal to the lesser of 85% ( 85 % ) of the fair market value of the stock on the date of purchase or 85% ( 85 % ) of the fair market value on the enrollment date . the espp is intended to qualify as an 201cemployee stock purchase plan 201d under section 423 of the internal revenue code . during 2008 , 2007 , and 2006 , 362902 , 120230 , and 124693 shares , respectively were purchased under the plan for a total purchase price of $ 8782 , $ 5730 , and $ 3569 , respectively . at december 27 , 2008 , approximately 663679 shares were available for future issuance . 10 . earnings per share the following table sets forth the computation of basic and diluted net income per share: .

Question: what was the estimated percentual increase in the expected volatility observed during 2007 and 2008?
Answer: 4.5%