A linear function $g(x)$ is defined by the equation $g(x)=ax+c$, where $a$ and $c$ are constants. The table shows some values of $x$ and their corresponding values of $g(x)$.

x	1	4	7	10
g(x)	12	27	42	57

If $x$ increases by 5, by how much does $g(x)$ increase?