<prompt> Translate the following text to EnglishKodi ya mapato ya mtu binafsi - ambayo, kwa nadharia ya upande wa usambazaji, inapaswa kuwa imeongezeka tangu viwango vilipopunguzwa - ilikua kwa kiwango cha asilimia 2.1 tu.  <response>: Individual income taxes--which, by supply-side theory, should have spurted since rates were cut--grew at only a 2.1-percent rate. 