why is falcon 25% slower on cpython 3.5 than on cpython 2.7

Question

I took the following picture from the falcon homepage: https://falconframework.org/

As we can see that falcon on python 2.7 runs 24k requests/sec and on python 3.5 it runs 18k requests/sec. What could be the reason? Is this a problem with python 3.5 itself?