80% from my efforts 20% from subbies. The actual amount is between myself, my accountant and the tax man. This figure did used to be slightly more toward subbie work, but one managed to make himself bankrupt whilst earning £35,000pa, and I have as yet not found a reliable replacement for him. The other decided that a job with the council would be nicer ( his wife earns good money)
For an idea of what people in my trade can earn, have a look at this site.
http://www.dentex-pdr.co.uk/earnings.php