The calculation of the basic and diluted earnings per share is based on the following data:

Year ended
31 Dec 2016
£m
Half year to
30 June 2017
£m
Half year to
30 June 2016
£m
Earnings
67.0Earnings for the purpose of basic earnings per share being net profit attributable to equity holders of the parent43.533.3
Number of shares
NumberNumberNumber
190,166,794Weighted average number of ordinary shares for the purposes of basic earnings per share190,274,928190,141,575
Effect of dilutive potential ordinary shares:
Share options
190,166,794Weighted average number of ordinary shares for the purposes of diluted earnings per share190,274,928190,141,575
Earnings per share
PencePencePence
35.2Basic22.917.5
35.2Diluted22.917.5
Headline earnings
£m£m£m
67.0Net profit attributable to equity holders of the parent43.533.3
Add back:
2.8Amortisation of acquired intangible fixed assets (net of tax)1.51.6
0.5Acquisition costs (net of tax)
70.3Headline earnings45.034.9
Headline earnings per share
PencePencePence
37.0Basic23.618.3
37.0Diluted23.618.3