The U.S. Citizenship and Immigration Services (USCIS) has published a fact sheet with information on the population of LOW-INCOME APPLICANTS that are eligible for naturalization. This fact sheet provides information on LOW-INCOME APPLICANTS with Lawful Permanent Residence (LPR) status, also known as Green Card holders. I have included the link to the USCIS fact sheet below.
Source of Information:
USCIS (USCIS.gov), USCIS Newsroom: Fact Sheets