3 years 2.67 per year
A contract must be in increments of $0.5m, which means, in order to have a 3 year deal, you must increase your winning bid to $9.0m. This would allow you to have a contract of $3.0m (2021).
Otherwise, with an $8.0m winning bid, your contract would have to be $4.0m (2020) or $8.0m (2019). What is contract would you prefer?