Takumi started studying how the number of branches on his tree changes over time.
The relationship between the elapsed time, $t$, in years, since Takumi started studying his tree, and the total number of its branches, $N(t)$, is modeled by the following function:
###$N(t)=63\cdot 2\^{\Large t}$
**Complete the following sentence about the yearly rate of change in the number of branches.**
Every year, the number of branches [[☃ dropdown 2]] by a factor of [[☃ numeric-input 1]].