50 percent? You are way off. I am willing to bet that 90 percent of people don’t know. I saw a little clip in one of my classes where they interviewed Harvard grads and only 1 out of 10 got it right.
And, honestly, to be fair, I think a lot of people learned it but have forgotten b/c it matters so little in one’s daily life. As my one friend said to me, “Who cares?”
Why would anyone forget?
Being a fisherman, it's really important to know these things, unless you just want to sit outside.