On its website, the Statesman Journal newspaper $($Salem$,$ Oregon, $2005)$ reports mortgage loan interest rates for $30-$year and $15-$year fixed$-$rate mortgage loans for a number of Willamette Valley lending institutions. Of interest is whether there is any systematic difference between $30-$year rates and $15-$year rates $($expressed as annual percentage rate or APR$)$ and, if there is$,$ what is the size of that difference. The following table displays the $30-$year rate and the $15-$year rate for each of nine lending institutions. Also given is the difference between the $30-$year rate and the $15-$year rate for each lending institution. Use the table to compare the $30-$year rates and the $15$year rates. Also, calculate the average of the differences between the rates. $($Input the amount as positive value. Round your answer to $4$ decimal places.$)$

$\backslash$table$[[$Lending Institution,$30-$ Year,$15-$Year,Difference$],[$Blue Ribbon Home Mortgage,$5\mathrm{.}113,4\mathrm{.}396,0\mathrm{.}717],[$Coast To Coast Mortgage Lending,$6\mathrm{.}298,3\mathrm{.}488,2\mathrm{.}810],[$Community Mortgage Services Inc.,$6\mathrm{.}316,3\mathrm{.}931,2\mathrm{.}385],[$Liberty Mortgage,$4\mathrm{.}555,3\mathrm{.}297,1\mathrm{.}258],[$Jim Morrison's MBI,$5\mathrm{.}613,-3\mathrm{.}265,2\mathrm{.}348],[$Professional Valley Mortgage,$6\mathrm{.}021,3\mathrm{.}756,2\mathrm{.}265],[$Mortgage First,$3\mathrm{.}005,3\mathrm{.}939,-0\mathrm{.}934],[$Professional Mortgage Corporation,$3\mathrm{.}277,3\mathrm{.}948,-0\mathrm{.}671],[$Resident Lending Group Inc.,$4\mathrm{.}352,3\mathrm{.}335,1\mathrm{.}017]]$