Here are a few data points for annual earnings to help you:
NCES Digest of Education Statistics, 2010
-Bachelor's Degree: $56,570
-High School Graduate: $32,270
NCES Digest of Education Statistics, 2011
-Bachelor's Degree: $57,130
-High School Graduate: $32,500
These can be broken down further, and can be reserached on the website (
http://nces.ed.gov/programs/digest/2011menu_tables.asp)
Having said that, it's not always about making the most money.
Personally, I'm a proponent of joining the military to help pay for your college. Not only do you get the GI Bill, but you can get all your tuition paid fo while on active duty, keeping your GI Bill for later. In addition, you may qualify for Pell Grants, which are loans you don't have to pay back. You can apply for them even if you're not in the military, though. I have a son in culinary school right now, using my GI Bill, and another 4 years behind him, so I'm keenly aware of the pros and cons of secondary and post-secondary education.
Disclaimer: I'm active duty Air Force with 19+ years of service. I entered with an associate's, completed a bachelor's and master's while in the military (didn't have to come out of pocket for either).
As for me, a bachelor's degree DID make a huge difference in my potential earnings. I went from a SSgt to a 2d Lt (doubled my pay initially), and you can Google military members pay charts to see the differences.