One fourth of the population would fall into this category. They would classify as tetrachromats, with four cones in their eyes. This allows them to see millions and millions of separate colors.
A BBC report highlights just how rare tetrachromats are. The mutation is due to a variation in a gene which influences the retinas' development.
This allows people like artist Concetta Antico to see colors invisible to most of the population.
So how many colors did you see? Are you a tetrachromat?