At its peak in 2007 it was worth some $65 billion, reckons Clare McAndrew, founder of Arts Economics, a research firm—double the figure five years earlier.

ArtsEconomics研究公司的创始人克莱尔·麦克安德鲁估算，在2007年的巅峰期，它的价值约为650亿美元，是五年前的两倍。