In the u. s. the amount in savings contributed to iras rose from $239 billion in 1992 to $3,667 billion by 2005, while overall savings actually dropped from low to lower. evidence suggests that , in the economy as a whole, increased savings in these retirement accounts: . are the negative results of a change in wage levels and higher work effort. b. the results of personal preference and intertemporal budget constraints. c. are being offset by negative savings of less saving in other kinds of accounts. d. the result of a higher interest rates and preferences about present consumption