In 2008 the Authors’ Licensing and Collecting Society (UK) commissioned a survey to examine author’s earnings.

Here’s what they found:

• The average (mean) annual earnings of a writer: £16,531
• The typical (median) earnings of a writer: £4,000
• 60% of people who saw themselves as ‘professional authors’ required a second source of income
• The average (mean) annual earnings of a writer (25-34): £14,564
• The typical (median) earnings of a writer (25-34): £5,000
• The average (mean) annual earnings of a writer (35-44): £24,533
• The typical (median) earnings of a writer (35-44): £18,000
• The average (mean) annual earnings of a writer (45-54): £35,958
• The typical (median) earnings of a writer (45-54): £14,250
• The genres that earned the most money (highest to lowest): TV writing, Theatre/film writing, Audio, internet and other, Books – fiction, Books – academic/educational, Books – children’s fiction, Newspapers/magazines and Books – non-fiction.

Source: What are Words Worth? The ALCS commissioned research carried out by Bournemouth University.