Sentence Correction

Americans were found to be more frustrated than angry, with 56 percent expressing frustration with the federal government, compared with 21 percent who said they were angry.

Please explain the functionality of the "with 56 percent expressing frustration with the federal government"
and "compared with 21 percent who said they were angry".

What is last part after the second ',' modifying.

This abstract is taken from reuters.

Gmat_War wrote:Americans were found to be more frustrated than angry, with 56 percent expressing frustration with the federal government, compared with 21 percent who said they were angry.

Please explain the functionality of the "with 56 percent expressing frustration with the federal government"
and "compared with 21 percent who said they were angry".

What is last part after the second ',' modifying.

This abstract is taken from reuters.

"compared with 21 percent who said they were angry." is modifying "with 56 percent expressing frustration with the federal government," and this one is modifying "Americans."

Gmat_War wrote:Americans were found to be more frustrated than angry, with 56 percent expressing frustration with the federal government, compared with 21 percent who said they were angry.

Please explain the functionality of the "with 56 percent expressing frustration with the federal government"
and "compared with 21 percent who said they were angry".

What is last part after the second ',' modifying.

This abstract is taken from reuters.

Also note that newspaper-level journalism has some habits with modifiers that can get you in trouble on the GMAT. Magazine-level journalism has (in theory) a longer editing cycle and fewer space restrictions.