Factor	Percentage of Cancer Cases
Tobacco	19.4
Diet	9.2
Overweight and obesity	5.5
Alcohol	4.0
Occupation	3.7
Radiation (UV)	3.5
Infections	3.1
Radiation (ionizing)	1.8
All environmental factors	42.7
Source: Parkin, D.M., L. Boyd, and L.C. Walker. 2011. Fraction of cancer attributable to lifestyle and environmental factors in the UK in 2010. British Journal of Cancer 105:S77-S81.