Delta, United, and American Airlines announced purchases of planes on July $18(7/18),$ February $12(\frac{2}{12}),$ and October $7(\frac{10}{7}),$ respectively.

Given the above information, calculate the cumulative abnormal return $($CAR$)$ for these stocks as a group. $($A negative answer should be indicated by a minus sign. Leave no cells blank $-$ be certain to enter $"0"$ wherever required. Do not round intermediate calculations and round your answers to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$