There has been a progressive decrease in population every year in this city.

这个城市的人口在逐年递减。

《新英汉大辞典》

And the fall of social average rates is the basic reason of the progressive decrease of the currency circulation speed.

而社会平均利润率的下降是货币流通速度递减的根本性原因。

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There is a progressive decrease in their caloric intake.

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In a progressive tax system, that also means that the amount of tax payable will be smaller since tax rates tend to decrease with taxable income (with some exceptions, of course).

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