are recorded at cost and are amortized over their respective estimated useful lives, and are reviewed for impairment in ac- cordance with SFAS No.  144 , “Accounting for the Impairment or Disposal of Long-Lived Assets” (see Note  5  to the Con- solidated Financial Statements). We are required to make judgments regarding the useful life of our intangible assets. With the implementation of SFAS  142 , we determined certain intangible assets to have indefinite lives based upon our analysis of the requirements of SFAS  No.  141 , “Business Combinations” (“SFAS  141 ”) and SFAS  142 . Under the provisions of SFAS  142 , we are required to test  these assets for impairment at least annually. The annual impairment tests have been completed and did not result in an  impairment charge. To the extent an impairment is identified in the future, we will record the amount of the impairment  as an operating expense in the period in which it is identified. In connection with a registration statement we filed in October  2003 , the Staff of the Securities and Exchange Com- mission commented on and sought additional support for the indefinite life designation of our trade names, marketing rights  and distributor network assets. Based on our assessment in responding to these comments, we recorded the following in the  second quarter of  2004 : (i) a one-time amortization charge of $ 1 . 2  million resulting from retroactive changes in the estimates  of the useful lives of certain intangible assets, which included the assignment of useful lives to our distributor network and  certain trademarks and trade names that were previously designated as indefinite lived assets; (ii) an entry to reduce intan- gible assets and retained earnings by approximately $ 8 . 8  million to reflect a reduction in the carrying amount of the mar- keting rights previously purchased from a group of controlling shareholders to its carryover basis; and (iii) an entry to  reclassify approximately $ 7 . 4  million from goodwill to distributor network and trade names and trademarks to retroac- tively reflect intangible assets acquired.  As a result of these changes we recorded an additional $ 0 . 9  million of amortization related to these assets during the  remainder of  2004  and will continue to recognize an additional $ 1 . 2  million of such amortization per year through the  remainder of the useful lives, which approximate  11  years as of December  31 ,  2004. The following table sets forth our operating results as a percentage of revenue for the periods indicated: RESULTS OF OPERATIONS Year Ended December  31 , 2002 2003 2004 Revenue 100.0% 100.0% 100.0% Cost of sales 19.8 17.9 16.8 Gross profi t 80.2 82.1 83.2 Operating expenses: Selling expenses 39.6 41.3 42.9 General and administrative expenses 29.6 29.4 29.3 Restructuring and other charges — .5 — Total operating expenses 69.2 71.2 72.2 Operating income 11.0 10.9 11.0 Other income (expense), net (.3) — (.3) Income before provision for income taxes  10.7 10.9 10.7 Provision for income taxes 4.0 4.0 3.9 Net income 6.7% 6.9% 6.8% 37