The 5-year returns of S&P500 index (which is made of 500 large stocks) are shown below.

S&P 500 Return in %	Year
18.25	2020
31.29	2019
-4.45	2018
21.69	2017
11.8	2016

Using the 5-year history, How much is the HIGHEST possible return of the S&P500 index in 2021, with 95% confidence? Enter your answer in the following format: + or - 0.1234 Hint: Use finance calculator. Do not enter answer as 12.34, enter it as 0.1234. Answer is between 0.3892 and 0.4611