I grew up at the bottom of a hill that is about 200 yards in elevation. The sign at the bottom said it was 14% grade. It is about 200 yards in [edit] length, The other side is around 8%.
My school was on the other side of the hill. It would snow.
Yes, I walked to school, uphill, in the snow, both ways.
I can also report that riding a bike up a 14% grade is a total *****. Coming straight down is a total thrill.