EXHIBIT 11.1 NATIONAL INSTRUMENTS CORPORATION AND SUBSIDIARIES STATEMENTS RE: COMPUTATION OF EARNINGS PER SHARE (In thousands, except per share data) Years Ended December 31, 1999 1998 1997 -------- -------- -------- Net income $45,248 $37,386 $33,625 ======== ======== ======== Basic earnings per share $ 0.91 $ 0.76 $ 0.69 ======== ======== ======== Weighted average shares outstanding-basic 49,776 49,248 48,845 ======== ======== ======== Diluted earnings per share $ 0.87 $ 0.73 $ 0.67 ======== ======== ======== Weighted average shares outstanding-diluted 52,203 51,150 50,484 ======== ======== ======== Calculation of weighted average shares: Weighted average common stock outstanding-basic 49,776 49,248 48,845 Weighted average common stock options, utilizing the treasury stock method 2,427 1,902 1,639 -------- -------- -------- Weighted average shares outstanding-diluted 52,203 51,150 50,484 ======== ======== ========