Since most reviews are in either an American or British context, it actually is burned into our psyche. An 80%, or a B, is a pretty passable grade overall ever since we were kids. A single 70%(or a C) can prevent you from getting into college, cost you scholarships, and in general ruin your entire rest of life and force you to go into a hellish minimum wage job and be a wage slave for the rest of your life.
This has literally happened to 5 people I know from high school. A single C.
Don't drag the british down with the Americans for this. We do a lot of shit wrong, but grades isn't it.
70% being a top grade is something well understood in the UK.