WFO Corporation has gross receipts according to the following schedule: 

Year 1  $ 21.00 million

Year 2  $ 25.00 million

Year 3  $ 20.00 million

Year 4  $ 29.50 million

Year 5  $ 35.00 million

Year 6  $ 23.00 million. 

If WFO began business as a cash-method corporation in Year 1, in which year would it have first been required to use the accrual method?