A study recently released by the Pell Institute for the Study of Higher Education shows that not only is the income gap between the richest and poorest Americans increasing, but the college-completion gap between them is growing, too.

Over the past 45 years, the percentage of students who coming from households with a total annual income of $34,000 or less that completed college rose from six to nine percent. However, students that came from more affluent homes saw an increase in completion rates from 44 to 77 percent.

That puts the college-completion gap between the poorest and richest students at a 46 percent difference.

Researchers cite several factors as to why this gap in completion rates might exist. There is a correlation between at-risk students and low-income students, and at-risk students are less likely to be academically prepared for college. They have less access to reliable transportation, and are more likely to have to work at least one job while in school.

Students who come from higher-income homes are more likely to attend four-year state and private colleges, compared to lower-income students who are more likely to attend community colleges and for-profit schools.

And obviously, one of the biggest obstacles for poorer students is the overall cost of college. Not only is tuition rising, but add in the price of books, room and board, and other associated costs with attending school, and affording college becoming more and more impossible.

This inability to afford school puts these students at a disadvantage when entering the workforce, as a bachelor’s degree is becoming a requirement in many fields. Without the degree, the students are pushed into lower-paying jobs and the unfortunate cycle continues.

Click here to read the full report from the Pell Institute.