How many cells are in the prophase stage?

About 1%

For any given sample of cells, about 1% of them are in prophase. This is because during the cycle, interphase takes up 90-95% of a cell’™s life, and the rest is taken up by prophase, metaphase, anaphase, telophase, and cytokinesis. This is according to a handout from the Division of Biological Sciences of the University of Montana.