Inverting the S&amp;P 500 numbers the grandparent posted.<p>On a practical level, inflation is always relative to <i>what you&#x27;re actually buying</i>.  If you&#x27;re buying S&amp;P 500 index funds, the inflation rate is the price appreciation of the S&amp;P 500.  If you&#x27;re buying real-estate, the inflation rate is the rate of increase in housing prices.<p>(Perhaps this is a bad example because you typically wouldn&#x27;t be buying stock index funds after 40 years of earning, but the point is to illustrate opportunity cost.  If someone&#x27;s goal is to pass wealth on to their children, for example, then the price of income-producing assets is a lot more relevant than the price of milk.)