Year Ended December 31, (in thousands, except per share data)       2000     1999     1998 Net revenue $ 268,836 $ 226,290 $ 171,298 Direct expenses:   Employee costs 78,051 61,224 46,878   Orthodontic supplies 21,274 17,136 13,287   Rent 23,973 18,624 14,128   Marketing and advertising 22,001 16,874 15,491     Total direct expenses 145,299 113,858 89,784 General and administrative 28,360 23,270 18,104 Depreciation and amortization 15,175 12,238 9,124 Operating profit 80,002 76,924 54,286 Interest expense (4,571 )  (2,599 )  (337 )  Interest income 840 395 617 Income before income taxes 76,271 74,720 54,566 Provision for income taxes 28,549 28,206 20,753 Net income before cumulative effect  of changes in accounting principles 47,722 46,514 33,813 Cumulative effect of changes in accounting  principles, net of income tax benefit (50,576 )  (678 )  — Net income (loss) $ (2,854 )  $ 45,836 $ 33,813 Net income (loss) per share:   Basic before cumulative effect of changes in accounting principles $ .99 $ .97 $ .71   Cumulative effect of changes in accounting principles (1.04 )  (.02 )  —   Basic $ (.05 )  $ .95 $ .71   Diluted before cumulative effect of changes in accounting principles $ .96 $ .96 $ .70   Cumulative effect of changes in accounting principles (1.02 )  (.02 )  —   Diluted $ (.06 )  $ .94 $ .70 Weighted average shares outstanding:   Basic 48,412 47,998 47,690   Diluted 49,845 48,643 48,502   Pro forma net income for change in accounting    principle effective January 1, 2000 N/A $ 32,326 $ 22,276   Pro forma net income per share diluted for change    in accounting principle effective January 1, 2000 N/A $ .66 $ .46 See accompanying notes.