In stead of design for P5-95 and therefore excluding 10% you could also strive to exclude as less as possible. Inclusive Design means to be aware of who you exclude.
Therefore Marijke Dekker and myself wrote about Exploring the boundaries of Design for All.
These thoughts will help you when you are designing for Tall People: 800k people in the Netherlands are taller than 190cm as a male or 180 cm as a female, or obese people : 20% has a BMI>30 kg/m*m. Office chairs are for example not garanteed for people>110kg while the heaviest person in the world was 625kg according to Guinnes Book of Records.
A few other numbers:
We have about 2.5 or 3 million people who can be called low literated and can’t understand our public transport messages. We have 60k wheelchair users and 300k scootermobiles. 2% do not have internet. this means 340k people in the Netherlands. 10% of the males are colour blind. We should be aware not exclude those people as users of our products and services by our design decisions.