The U.S. economy expanded at a 4.2 percent annual rate in April, May, and June. The second-quarter growth figure is one-tenth of a percent higher than initial estimates.
"The economy is in good shape," according to PNC Bank Chief Economist Gus Faucher. He writes that this is the best "year-over-year increase in three years."
But Faucher also says growth above four percent is "unsustainable" and the economy is "set to slow somewhat in the second half of 2018," and hit 3.4 percent for the whole year. He predicts U.S. economic growth will slow further in 2019 and 2020 as the "stimulus from tax cuts and spending increases fades."
Wednesday's report from the Commerce Department is a routine revision made as more complete data becomes available.
Growth figures were boosted by a decline in imports, particularly petroleum, and by some temporary factors.
One of them is a surge in soybean exports, which were rushed at a faster-than-usual pace to beat tariffs imposed by China, in retaliation for new tariffs imposed by the Trump administration on Chinese goods.
The new second quarter figures are nearly double the performance in January, February, and March.
美国经济在4月、5月和6月以4.2%的速度增长，这一增速较此前公布的第二季度初值的增速高出0.1个百分点。
“经济状况良好，” PNC银行首席分析师福奇尔表示。他写道，这创下“三年来最好的同比增长。”
但福奇尔也表示，超过4%的增速是“不可持续的”，经济“将在2018年下半年有所放缓”，全年增速将达到3.4%。他预计，随着“减税和支出增长的刺激措施逐渐消退”，美国经济增速将在2019年和2020年进一步放缓。
美国商务部周三发布的报告是例行修订，因为收集到了更完整的数据。
经济数据增长是受到了进口下降的提振，尤其是石油进口下降，以及一些暂时性因素的影响。
其中一个暂时性因素是大豆出口激增。为了避免赶上中国对特朗普政府新关税的报复性关税，中国以比往常更快的速度进口大豆。
第二季度修正值几乎是1月、2月和3月经济增速的两倍。