Question 926017
in {{{x=1996}}} ->  {{{y=16400}}}

in {{{x=2005}}} ->   {{{y=19820}}}

rate of change :

{{{(19820-16400)/(2005-1996)=(3420)/9=380}}} 

On average, rate of change is {{{380(lb/yr)}}}  between {{{1996}}} and {{{2005}}}.