illumina , inc . notes to consolidated financial statements 2014 ( continued ) advertising costs the company expenses advertising costs as incurred . advertising costs were approximately $ 440000 for 2003 , $ 267000 for 2002 and $ 57000 for 2001 . income taxes a deferred income tax asset or liability is computed for the expected future impact of differences between the financial reporting and tax bases of assets and liabilities , as well as the expected future tax benefit to be derived from tax loss and credit carryforwards . deferred income tax expense is generally the net change during the year in the deferred income tax asset or liability . valuation allowances are established when realizability of deferred tax assets is uncertain . the effect of tax rate changes is reflected in tax expense during the period in which such changes are enacted . foreign currency translation the functional currencies of the company 2019s wholly owned subsidiaries are their respective local currencies . accordingly , all balance sheet accounts of these operations are translated to u.s . dollars using the exchange rates in effect at the balance sheet date , and revenues and expenses are translated using the average exchange rates in effect during the period . the gains and losses from foreign currency translation of these subsidiaries 2019 financial statements are recorded directly as a separate component of stockholders 2019 equity under the caption 2018 2018accumulated other comprehensive income . 2019 2019 stock-based compensation at december 28 , 2003 , the company has three stock-based employee and non-employee director compensation plans , which are described more fully in note 5 . as permitted by sfas no . 123 , accounting for stock-based compensation , the company accounts for common stock options granted , and restricted stock sold , to employees , founders and directors using the intrinsic value method and , thus , recognizes no compensation expense for options granted , or restricted stock sold , with exercise prices equal to or greater than the fair value of the company 2019s common stock on the date of the grant . the company has recorded deferred stock compensation related to certain stock options , and restricted stock , which were granted prior to the company 2019s initial public offering with exercise prices below estimated fair value ( see note 5 ) , which is being amortized on an accelerated amortiza- tion methodology in accordance with financial accounting standards board interpretation number ( 2018 2018fin 2019 2019 ) 28 . pro forma information regarding net loss is required by sfas no . 123 and has been determined as if the company had accounted for its employee stock options and employee stock purchases under the fair value method of that statement . the fair value for these options was estimated at the dates of grant using the fair value option pricing model ( black scholes ) with the following weighted-average assumptions for 2003 , 2002 and 2001 : year ended year ended year ended december 28 , december 29 , december 30 , 2003 2002 2001 weighted average risk-free interest rate******* 3.03% ( 3.03 % ) 3.73% ( 3.73 % ) 4.65% ( 4.65 % ) expected dividend yield********************* 0% ( 0 % ) 0% ( 0 % ) 0% ( 0 % ) weighted average volatility ****************** 103% ( 103 % ) 104% ( 104 % ) 119% ( 119 % ) estimated life ( in years ) ********************** 5 5 5 .

year ended december 28 2003: weighted average risk-free interest rate: -3.03
expected dividend yield: 0
weighted average volatility: -103
estimated life ( in years ): 5
weighted average fair value of options granted: 3.31
year ended december 29 2002: weighted average risk-free interest rate: -3.73
expected dividend yield: 0
weighted average volatility: -104
estimated life ( in years ): 5
weighted average fair value of options granted: 4.39
year ended december 30 2001: weighted average risk-free interest rate: -4.65
expected dividend yield: 0
weighted average volatility: -119
estimated life ( in years ): 5
weighted average fair value of options granted: 7.51

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Questions:
what is the difference between the weighted average risk-free interest rate of 2003 and 2002?
what is the weighted average risk-free interest rate of 2002?
how much does that difference represents in relation to weighted average risk-free interest rate of 2002?

Answers:
-0.70
3.73
-18.8%