Actually, that's not what the chart says. It's not maximum speeds, it's all speeds. That includes many circumstances where you can't go that fast, e.g. due to s

Actually, that's not what the chart says. It's not maximum speeds, it's all speeds. That includes many circumstances where you can't go that fast, e.g. due to slow traffic, accidents, speed limits etc. So 30% of all speeds surely is a lot.