I presume they are sourcing their statistics from here: http://utgafuskra.is/statistics.jsp?lang=1 http://utgafuskra.is/statistics.jsp?lang=1 About 5 per 1,000

I presume they are sourcing their statistics from here: http://utgafuskra.is/statistics.jsp?lang=1 http://utgafuskra.is/statistics.jsp?lang=1 About 5 per 1,000 in a given year seems roughly correct. I don't know how you would calculate the figure for publications in a lifetime, especially since I presume many authors write multiple books in their lifetime.