The tradition of percentage notation using the % sign is wrong because the divisor is 100, which obviously has two zeros. Percentage should be noted as ‰, but that is already occupied by another obvious error in tradition, because that means parts per thousand, and a thousand obviously should have three zeros in its divisor.
There is an obvious way of correcting this obvious error but it would create too much confusion. Percentages could be written 1/00, and parts per thousand as 1/000 and parts per ten thousand as 1/0000, but because of the inertia of the existing wrong-headed notation that would create confusion. Beyond that the convention could be using a number for the quantity of zeros. One part per thousand could be alternately written 1/3, and one part per million as 1/9. This follows the standard scientific notation except that it is more condensed and doesn’t require superscripts and subscripts. But, that doesn’t work very well because the notation would conflict with the standard way of writing fractional numbers.
Here is a system that would work. Say “parts per hundred” when you see p/00. The letter p represents the word parts, the slash / represents the divisor word per, and the number of zeros 00 represents the number of zeros in the divisor. Thus seeing a number followed by p/00, you would say the number and then say “percent,” or if it was a number followed by p/000 you would say the number followed by “per thousand,” or if it was a number followed by p/0 you would say “parts per ten.” This system of nomenclature could be easily raised to any given power by replacing the number of zeros with a numeral. Thus, a number followed by p/9 would be said as the number followed by “parts per billion,” as there are nine zeros in a billion.
The same procedure works for these divisor numbers of any size, but it might become common to drop the nomenclature and for a number such as a number followed by p/4 to just say “parts per four” rather than the more clumsy “parts per ten thousand.” That is a reasonable development from the basic system, but the basic system would be used most of the time.
If society learns to replace the % sign with p/00 we will make the meaning of the numbers more obvious.