If conditions hold, 2018 will be the fifth year of double-digit gains.

Juniper Research also predicted that Apple will account for about 50% of all OEM pay users globally by 2020.

The estimate is a drop from the committee's last estimate of $10.1 billion in lost revenue between 2017 and 2021.

Non-revolving lending by the federal government, which is mainly for student loans, increased by $20.2 billion.