How much geniune gold is there in your gold?

The "pure" gold jewellery we purchase should have a the letters CT or KT stamped onto it.
As the American spelling of KARAT is being more universally adopted the CT markings on gold will in all likelihood over a period of time be replaced with "Kt"
The CARAT system is used for both GEMSTONES & GOLD
Although the spelling is identical that is the only thing they have in common
CARAT (mass) - a unit of weight for precious stones and pearls. 1 carat  = 200 milligrams or 0.2 grams
CARAT (purity) - a measure of the purity of gold.
The American and Canadian spelling of KARAT in respect of gold has created a definite gap between the commodities.
Now that CARAT vs KARAT has been cleared up - how much gold are we actually getting for our hard earned cash.
24 karats = 100% gold therefore 1 karat = 4.17 % gold

  9 karat = 37.5% gold      
10 karat = 41.7% gold
14 karat = 58.38% gold
18 karat = 75.06% gold
22 karat = 91.74% gold
24 karat = 100% gold (pure gold)