In reply to Debasreeta.

Thank you for asking a mathematics question that I understand. To calculate a ratio, you start with the total number (23 + 67) and divide it into each segment. For example, the proportion of females is 23 / (23+67), or 23/90, or 0.25555. Male proportion is 67 / (23+67), or 67/90, or 0.74444. Add the two together and account for a small rounding difference, and the total approaches 1.0. In SAS code, the formula for female_proportion would look like:
female_proportion = female_count / (female_count+male_count);