Graph based on a dataset compiled by Jisc of 6,741 article processing charges (APCs) paid by 22 UK higher education institutions in 2014. It shows the average APC price paid to the top 20 largest publishers (largest in terms of number of APCs).
The average price paid for an APC often differs from the prices listed on publisher/journal websites.
The average APC is £1,575.
Underlying data available here: http://figshare.com/articles/APC_data_2014/1311672