What two processes emit the most carbon in the united states

The two processes that emit the most carbon in the United States are:
1. electricity production: electricity produces the largest portion of carbon in the United States. About 67% of the electricity come from burning fossils fuels, which are majorly coal and natural gas. 29% of carbon emission comes from electricity. 
2. Transportation: fossil fuels are burned in almost all the vehicles in USA. 27% of the carbon emission come from the fuels used in the vehicles.  

The density would be 1.622