A simple survey of Google's search engine:
NEWS articles searched (this will include duplicate articles printed in different publications and includes international and historical uses of the word):
"Right Wing" 5,170 matches
"Left Wing" 3,760 matches
"Extreme Right Wing" 183 matches
"Extreme Left Wing" 13 matches
"Right Wing extremists" 323 matches
"Left Wing extremists" 4 matches
"conservative" matches 8,990; the term "conservative estimates" account for 121 matches
"liberal" 8,620 matches; the term "liberal estimates" did not appear at all
"conservatives" 4,770 matches
"liberals" 3,260 matches
"Republican" 8,720 matches
"Republicans" 10,500 matches
"Republican Party" 2,680 matches
"Democrat" 12,100 matches
"Democrats" 11,400 matches
"Democrat Party" 320 matches
"Democratic Party" 5,170 matches
"Progressives" 226 matches
"Socialist" 2,200 matches
"Socialists" 630 matches
"Socialist Party" 687 matches
"Communist" 5,950 matches
"Communists" 1,240 matches
"Communist Party" 2,200 matches
"Green Party" 692 matches (there is an nternational Green Party)
"Libertarian" 463 matches; with 73 matches for"Libertarian Party"
By the way, I did a News search of "Media Bias" and found 63 matches.
A little varation:
"Right Wing radicals" 1,490 matches
"Left Wing radicals" 1,920 matches
Lefties are more radical. Less bias here. Lefties are radical.