The decline started in the 1950s, when manufacturing generated a sturdy 28% of the national income, or gross domestic product, and employed one-third of the workforce.
				出自-2013年6月阅读原文
				By last year, Wall Street traders, bankers and those who deal in real estate generated 21% of the national income, double their share in the 1950s
				出自-2013年6月阅读原文
				It generated just 12% of the gross national income.
				出自-2013年6月阅读原文