Savant skills included more fully developed talents, such as being able to name the elevation of both the sun and the moon at any time of day, on any specified date; being able to name the day of the week for any date in the distant past or future (a talent known as calendrical calculation) and perfect pitch. Importantly, the abilities and the skills had to be exceptional by the standards of the general population, but also well above the individual's overall level of ability. In total, roughly 30 per cent had some kind of special ability (Philosophical Transactions of the Royal Society B, vol 364, p 1359).