It is also worthy of note that recent surveys suggest that fewer than 10% of those people suffering with visual impairment can read Braille.
Physical condition
Evacuation studies have been carried out which suggest a general guide to the number of people who might require special assistance in an evacuation. Studies have concluded that, on average, some 3% of people in such buildings cannot or should not evacuate using multiple flights of stairs. Similarly it should be assumed that 3% of the members of a large public crowd may require