For humans, our bodies are made of 18.5% Carbon.
Additional info about our body composition...we are also made up of:
65% Oxygen
9.5% Hydrogen
3.2% Nitrogen
1.5% Calcium
1% Phosphorus
0.4% Potassium
0.3% Sulfur
0.2% Sodium
0.2% Chlorine
0.1% Magnesium
Less than 1% of Boron, Chromium, Cobalt, Copper, Fluorine, Iodine, Iron, Manganese, Molybdenum, Selenium, Silicon, Tin, Vanadium, and Zinc.