A Chemistry $20$ student uses a thermometer and a hot plate and measures the boiling point of ethyl alcohol to be $72\mathrm{.}6C.$ Then, she looks in a reference book and finds that the actual boiling point of ethyl alcohol is $78\mathrm{.}4C.$ What is her percent error?

Do not show your work in the space provided.

Record only your final answer with the correct number of significant digits and the proper units.