<prompt> Translate the following text to EnglishUtafiti wa hivi karibuni ulikadiria kuwa athari ya utajiri ya senti 3 hadi 4 inaweza kuelezea asilimia mbili kwa tano hadi nusu ya kupungua kwa kiwango cha akiba ya kibinafsi tangu 1988.  <response>: A recent study estimated that a wealth effect of 3 to 4 cents could explain two-fifths to about half of the decline in the personal saving rate since 1988. 