The table shows the population of Nepal (in millions) as of June 30 of the given year. Use a linear approximation to estimate the population at midyear in $1984$. Use another linear approximation to predict the population in $2006$. (To approximate a derivative, average the secant slopes "closest" to the point.)
$$\begin{array}{|c|c|c|c|c|c|} \hline {t} & 1980 & 1985 & 1990 & 1995 & 2000\\ {N(t)} & 15.0 & 17.0 & 19.3 & 22.0 & 24.9 \\ \hline \end{array}$$

In $1984$: million
In $2006$: million