As we've learned over the past few weeks talking to Colorado teenagers growing up in poverty, the lower rungs of the economic ladder are a tough perch from which to even think about going to college, let alone gain entrance -- and then pay for the education.

Now we learn from a new report  from University of Pennsylvania’s Alliance for Higher Education and Democracy and the Pell Institute for the Study of Opportunity in Higher Education that the likelihood of students finishing their degree is also affected by their economic status.

The percentage of students from the lowest-income families -- those making $34,160 a year or less -- earning a bachelor’s degree inched up just three points from 1970 to 2013, rising to 9 percent from 6 percent. College completion for students from the wealthiest families rose dramatically, though, climbing to 77 percent from 44 percent.

Other findings:

  • If they do further their education past high school, students from the poorest families are much more likely to attend two-year programs -- and those have lower completion rates.
  • College costs more than twice what it did in 1975 while Pell grants for lower-income students covered 67 percent of college costs in 1975 but only 27 percent in 2012.
  • Almost all students from highest income families wrap up their bachelor's degree by the time they turn 24, while 21 percent of students from the poorest families are done by the time they reach the same age.

This is sobering news for individual students who work hard and play by the rules. It also bodes ill for a country with a widening gap between rich and poor.

‘If anything, the returns to education, the benefits from attaining more education, have been growing over the last 20 years,’’ said David Zimmerman, an economics professor at Williams College. ‘‘So to the extent that the education gap is widening between students from more and less advantaged families, then the predicted gap in earnings would widen, as well.’’

The Wall Street Journal was among many news organizations to pick up the report:

“Education is one of the levers that we have in place to address income inequality. It offers the promise of achieving the American dream,” said Laura Perna, executive director of the Penn program. Yet the study’s findings suggest that “education isn’t fully living up to this promise.”

You can download and read all of the details in The Indicators of Higher Education Equity in the U.S. — 45 Year Trend Report. It was researched and published jointly by the Pell Institute and the Alliance for Higher Education and Democracy.