There are different shapes to the mouth across populations, but there are also many different ways of whistling. What percentage of the population can whistle? This whistling ability is not equal in all population, in Western countries for example, they do not know how to ululate.
There are no scientific polls on the number of people who can't whistle. However, in an informal internet poll, 67 percent of respondents indicated they can't.
i.e. Whether you have the ability to whistle, irrespective of whether you actually do, or whether whistling is acceptable in the country where you live.
Lots of non-whistlers think of whistling ability as a genetic trait, like attached earlobes or blue eyes. They've never figured out how to whistle.
How many of these simple things are not in your bag of tricks? tongue; Whistle; Shuffle cards; Touch their toes without bending their knees.