More Americans are buying organic fruit and vegetables and products made with organic ingredients. The amount $A(t)$, in billions of dollars, spent on organic food and beverages $t$ years after 1995 can be approximated by
$$
A(t)=2.43 e^{0.18 t}
$$
a) Estimate the amount that Americans spent on organic food and beverages in $2009 .$
b) Estimate the rate at which spending on organic food and beverages was growing in $2006 .$