Fifteen years ago, the world’s billionaires collectively had $4.5 trillion. 15年前，全球亿万富翁的财富总和为4.5万亿美元。 By 2024, their wealth had more than tripled to $14.2 trillion. 到2024年，他们的财富增长了两倍多，达到14.2万亿美元。 Now, their combined wealth totals $20.1 trillion — an amount…