The industry is worth $2.5 billion in consumer dollars. or $1.8 billion in what the publishers earn. Foreign rights(and stock) account for $220 million of the that. Direct sales by publishers are estimated to be 15% of the market (I'm assuming of publishers' revenue) or $270 million.
Education is 40% of the pie, and trade is 60%, which surprised me given that education is everything-but-trade. Trade books are the sort of books you buy in a bookshop, and education includes, primary, secondary, tertiary, scholarly and reference.
9% of the market is trade children's, which is an understatement as children's books are sold to a lot of schools, so maybe 12%. Adult trade fiction is 15% of the market and adult trade non-fiction is 36% of the market. Adult trade non-fiction includes narrative non-fiction as well as self-help and say cookery (a form of self-help?)
Dividing up the bookselling market by type of bookseller: the chains have 55% and independents 20% and the DDSs (Target, Kmart, Woolworths) 25%. The DDS share has grown sharply in the last 10 years.
Online sales are estimated to be $100m or 5% of the market.
What's interesting is how much the figures bounced around when I tried to nail them down.