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$],[$$$,10,\%,$$$,1,367],[520,,11,\%,1,793],[770,,16,\%,229,716],[18,000,,13,\%,276,052],[21,100,,,,]]$