$"[$I$]$t seems quite possible to me that inflation rates will average $7$ percent in future years....So there we are..$\mathrm{.}7$ percent after taxes and before inflation; and maybe zero percent after taxes and inflation. It hardly sounds like a formula that will keep all those cattle stampeding on TV$."($Warren Buffett $1977,$ How inflation swindles the equity investor$)$Which rule is Buffett using in the above passage?Rule $1$ of natural logarithms The Rule for the approximate growth rate in natural logarithms The Rule of $70$ The Ratio Rule