The Federal Reserve Bank of New York published a Student Debt Overview and on page 10 they have a chart of the distribution of student loan balances. The numbers are a couple years old now and probably grown a bit since then but not drastically.
Note that the chart includes all borrowers including people who went to grad school and professional school like law school and med school. So the larger balances are going to be mostly people with professional degrees like lawyers and doctors and there are much fewer people with just a bachelors degree who have 6 figure debts.
Here's a chart :
|source : FRBNY Consumer Credit Panel / Equifax|
And a table :