The following three defense stocks are to be combined into a stock index in January $2016($perhaps a portfolio manager believes these stocks are an appropriate benchmark for his or her performance$)$: Suppose that Douglas McDonnell shareholders approve a $3-$for$-1$ stock split on January $1,2017.$

$\backslash$table$[[,,$Price$],[,$Shares,,,,$],[($millions$),\frac{1}{1}\frac{?}{16},\frac{1}{1}\frac{?}{17},\frac{1}{1}\frac{?}{18},,],[$Douglas McDonnell,$545,$$$80,$$$83,$$$98,],[$Dynamics General,$460,70,63,77,],[$International Rockwell,$190,99,88,91,]]$

a$.$ What is the new divisor for the index? $($Do not round intermediate calculations. Round your answer to $3$ decimal places.$)$

New divisor

b$.$ Calculate the rate of return on the index for the year ending December $31,2017,$ if Douglas McDonnell's share price on January $1,2018,$ is $$30\mathrm{.}04$ per share. $($Do not round intermediate calculations. Enter your answer as a percent rounded to $2$ decimal places.$)$

Rate of return

$\%$