The table shows how the percent of women in the civilian workforce has changed from 1970 to 2010
$$\begin{array}{l|c} \text { Year } & \begin{array}{c} \text { Percent of Women in } \\ \text { the Workforce } \end{array} \\ \hline 1970 & 43.3 \\ 1975 & 46.3 \\ 1980 & 51.5 \\ 1985 & 54.5 \\ 1990 & 57.5 \\ 1995 & 58.9 \\ 2000 & 59.9 \\ 2005 & 59.0 \\ 2010 & 58.6 \end{array}$$
(a) Use a calculator to find the least-squares regression line for these data, where $x$ is the number of years after 1970
(b) Based on your result from part (a), write an equation that yields the same $y$ -values when the actual year is entered.
(c) Predict the percent of population of women in the civilian workforce in 2015 .