Below are returns on the stock A and S&P500 index. All numbers are in decimals (-0.0222 is equivalent to -2.22%).

A S_P500

-0.0222 0.0032

-0.0048 -0.0058

0.1333 0.0434

0.0765 0.1081

-0.0161 -0.0121

0.1250 0.1400

0.0145 0.0368

-0.0475 -0.0454

0.0430 0.0577

-0.0260 -0.1374

0.0071 0.0064

0.0249 0.0186

0.0850 0.0215

-0.0624 -0.0752

0.0933 0.0365

0.0456 0.0528

-0.0632 -0.0131

0.0450 0.0009

0.0200 0.0017

0.0280 0.0985

What is the sample standard deviation of the S&P500 returns?

answer in decimals and round to the fourth decimal