If you're identifying color for pretty much anything digital, you're working in an RGB colorspace. If the project you're working on requires percentage representation, mint green is made of 60% red, 100% green, and 60% blue.
If you're identifying color for a print project, you're most likely using a CMYK colorspace—the percentages are 40% cyan, 0% magenta, 40% yellow, 0% black.