Progress Bar - How do you assume decimal values?

By learning, I'm creating a good beast in C # and I make a progress bar the life bar, but I need to decrease a decimal value and apparently progress only assumes int values. How can I make it display decimal values such as 99.2%?

The Progress bar is naturally set to a minimum of 0 and a maximum of 100. Line that decreases in life:

lifeP1.Value -= (int)(ataque2);