The net worth for the Thompsons has increased by $60,000 in 2019. During 2019, the Thompsons put $3000 in an IRA out of their checking account. The Thompsons also made a $25000 down payment on a $100,000 vacation home, using a money market account. Investment the Thompsons own grew by $30,000, and they saved $20,000 in an FDIC insured savings account. The Thompsons pay a monthly mortgage with a $1500 principal and interest payment. Assuming no other changes in the Thompsons financial situation in 2019 how much principal did they pay on their mortgage during the year?