I'm having difficulty finding a definitive way to determine whether I can use a percentage measure as an independent variable in multiple linear regression or not.
From my understanding, the percentage can't be considered a true continuous measure for some reason and violates some assumptions of the regression model.
Edit 1: For example, I have seen the argument that percentage data is discrete because the underlying data that the percentages are calculated from is discrete.
Can someone explain why percentages aren't true continuous measures and in what cases I could use a percentage as an independent variable?
Edit 2: For further clarity, I will explain what I'm hoping to accomplish specifically below here. The goal is to use a dependent variable (length of time) and claim it explained by several independent variables (some dummies, one a percentage that isn't restricted to any certain values for any observation). I know the assumption for linear regression is that the independent variables will be continuous measures, which is why I utilize dummy variables for the dichotomous categorical variables. I'm just trying to make sure I don't need to utilize a different analytical technique altogether because of the percentages being technically discrete (is this even necessarily true?).
Edit 3: In the interest of complete specificity,
DV - Length of maternity leave taken. IV's - percentage of normal salary paid by employer during leave, and other dummies not relevant to the question.