PMT and Amortization Formulas

Scenario:
Loan: $100,000
Terms: 360 Months (paid monthly)
Interest Rate: 5%

How do I calculate total principal paid in year 2 (i.e months 13-24) and in year 3 (months 25-36). I need to be able to do this without creating a full amortization schedule and referring to it. Thanks in advance.