NaN% is the percentage representation of the fraction sitemap.xml/undefined. This unusual result comes from trying to turn an undefined division into a percent, which simply doesn’t produce a real number.
The fraction sitemap.xml/undefined itself is meaningless in ordinary math because you can’t divide by something that isn’t defined. It’s like asking how many apples you have if the number of apples is unknown—there’s no answer you can write down.
When you see NaN% you’re really seeing a placeholder that says “not a number.” It tells you that the calculation can’t be completed, not that there’s a hidden value waiting to be discovered.
In practice, you’ll want to avoid this kind of fraction. Make sure both the numerator and the denominator are known numbers before you try to turn them into percentages. This keeps your data clear and your reports easy to read.
