I think you can easily get your answer here:
http://davidmlane.com/hyperstat/z_table.html
For a normal curve, what percentage of values falls beyond two standard deviations from the mean?
2 answers
Read from the following table:
https://www.stat.tamu.edu/~lzhou/stat302/standardnormaltable.pdf
You will see that 2.275% of data falls beyond μ+2σ and another 2.275% of data falls below μ-2σ.
https://www.stat.tamu.edu/~lzhou/stat302/standardnormaltable.pdf
You will see that 2.275% of data falls beyond μ+2σ and another 2.275% of data falls below μ-2σ.