Partly paid shares outstanding issued under the Santos Executive Shar Plan; options outstanding issued under the Santos Executive Share Option Plan; and reset convertible preference shares have been classified as potenti al ordinary shares and included in the calculation of diluted earnings per share. The number of shares included in the calculation are those assumed to be issued for no consideration, being the difference between the number that would have been issued at the exercise price and the number that would have been issued at the average market price. During the year, 715,000 (2003: 1,250,000) options an 50,000 (2003: 35,750) partly paid shares were converted to ordinary shares. 6,000,000 redeemable convertible preference shares were not dilutive and wer e excluded from the calculation of diluted earnings per share. Annual Report 2004 69 Consolidated 2004 2003 21. Earnings per Share $million $million Earnings used in the calculation of basic earnings per share reconciles to  the net profit after tax in the statement of financial performance as follows: Net profit after income tax 379.9 327.0 Less special dividend on redeemable convertible preference shares (14.3) – Earnings used in the calculation of diluted earnings per share 365.6 327.0 Less dividends paid on reset convertible preference shares (23.0) (23.0) Earnings used in the calculation of basic earnings per share 342.6 304.0 2004 2003 Number of shares The weighted average number of shares used for the purposes of calculatin g diluted  earnings per share reconciles to the number used to calculate basic earnings per  share as follows: Basic earnings per share 584,924,130 583,432,623 Partly paid shares 100,722 112,876 Executive share options 755,897 164,841 Reset convertible preference shares 39,367,128 50,946,143 Diluted earnings per share 625,147,877 634,656,483