Stevenson and Wolfers provide a number of possible reasons why this occurred, including non-comparable data over time, and increasing income inequality in the US during this period.

史蒂文森和沃尔弗斯给出了很多可能因素，解释造成此现象发生的原因，其中包括随着时间的消逝数据的不具可比性和这段时期内美国收入增加的日渐不平等。

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Cell phone use has blurred the boundaries between work and non-work time, increasing stress and tension within families and between friends.

使用手机模糊了工作时间和非工作时间之间的界限，增加了家庭和朋友之间的压力和紧张气氛。

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There are other signs of overheating: inflation for non-tradable products in Chile is 6.4% and Brazilian wages are increasing at double-digit rates.

此外还有其他经济过热的迹象：在智利非流通产品的通货膨胀为6.4%。巴西的工资也以两位数的速度增长。

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Remember how he promised to pay for a cut in inheritance tax by increasing tax on non-doms?

BBC: The UK's 50p rate: Tax or symbol?

Increasing demand for non-tradable services should do just as well, as the years before the crisis attest.

ECONOMIST: Economics focus

But it's going to take a long while: At JPMorgan and other banks, charge-offs and non-performing assets are increasing and won't peak anytime soon.

FORBES: Banking