In addition to price$-$weighted and value$-$weighted indexes, an equally weighted index is one in which the index value is computed from the average rate of return of the stocks comprising the index. Equally weighted indexes are frequently used by financial researchers to measure portfolio performance.

The following three defense stocks are to be combined into a stock index in January $2022($perhaps a portfolio manager believes these stocks are an appropriate benchmark for his or her performance$)$:

Shares $($millions$)$ Price

$1/1/221/1/231/1/24$

Douglas McDonnell $350$ $ $65$ $ $69$ $ $81$

Dynamics General $450251933$

International Rockwell $210544357$

the rate of return on an equally weighted index of the three defense stocks for the year ending December $31,2022$ is $-12\mathrm{.}77\%$

If the index value is set to $100$ on January $1,2022,$ the index value on January $1,2023$ would be $87\mathrm{.}23.$

Now the part you solve: What is the index return for $2023?$

Note: Do not round intermediate calculations. Enter your answer as a percent rounded to $2$ decimal places.