Solve for the unknown number of years in each of the following. $($Do not round intermediate calculations and round your answers to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

$\backslash$table$[[$Present Value,Years,Interest Rate,,Future Value$],[660,,8,\%,1,604],[910,,12,,2,671],[19,400,,18,,418,534],[22,500,,14,,425,658]]$