How to Round Down

[mykrobinson]

I have an expression to calculate a person's age based on today minus the birthday:

Number(HOUR(TODAY()-[DOB])/365.25/24)&" yr"

I am finding expressions for rounding up, but how do I get it to always round down until the birthday has actually passed? I had an entry today that shows the person to be 75 years old, but they are still 74 for another week.

Thanks