<prompt> Translate the following text to EnglishIngawa hakuna ushahidi wa empirical kuunga mkono au kukataa nadharia kuhusu utajiri na WTP, WTP kwa miaka ya maisha ya ziada na wazee inaweza kwa sehemu kutafakari nafasi yao ya utajiri vis vis respondents wa umri wa kati.  <response>: While there is no empirical evidence to support or reject hypotheses regarding wealth and observed WTP, WTP for additional life years by the elderly may in part reflect their wealth position vis a vis middle age respondents. 