Echo JS 0.11.0

Where does this figure "50%" come from?

In the article :
236M    jntar.tgz     
406M    tar.tgz

That clearly demonstrates (choose) :
1) the only good answer is always 42
2) I suck and believe that halving size is a 50% improvement
3) this number is (statistically) meaningless

Haha thank you for the honesty!