John borrows 130,000 for 30 years and makes only the annual interest payments to the lender. He makes annual contributions to a sinking fund earning 6.5% to raise money to pay off the principal. For the first 10 years his deposits to the sinking fund are Y, for the next 10 years his deposits are 2Y, and for the last 10 years his deposits are 3Y. All deposits to the sinking fund are made at the end of the year. Find Y.