The Federación de Gremios de Editores de España (Spanish publishers association) has undertaken a survey into the country's publishing market, surveying over 300 publishing firms in order to build a comprehensive report which tracks publisher revenues, average book price, best-performing genres, share of digital and much more.
The IPA has produced an English-language adaptation of the full study which you can read here. The original Spanish-language report is available from the FGEE website.