<prompt> Translate the following text to EnglishKiwango cha maisha cha watu wa Marekani kinategemea kiwango cha GDP kwa kila mtu, ambacho kimekuwa kikiongezeka mara mbili kila baada ya miaka 35.  <response>: Living standards can be compared in terms of real GDP per capita, which historically in the United States has doubled every 35 years. 