How old are cats to human years?

I know dogs age is a ratio of 7 years to 1 human year. How do you figure the actual age of a cat who is 15 in human years?
Answers:
here's a conversion chart

http://cats.about.com/cs/healthissues/a/...

that will show you a cat's lifespan from 1 to 20 human years (Or 15 to 96 cat years)

here's another chart

http://www.xmission.com/~emailbox/cat_ag...

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101 year old cat

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It is the same with cat years. So it would be 15x7= 105(?)

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age in human years but they live for 18 years max so your cat has about 3 more years left maybe even 4.

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A 15 year old cat is approximately 74 in human years. At 20 the cat would be 94. At 10, 54 years.