Sarah currently has $617,000 saved in her retirement account and will continue to make annual payments of $4,000 into her account until retirement. Her twin sister, Andrea, currently has $471,000 in her retirement account. Andrea would like to have the same amount saved up as Sarah when they both retire in 21 years. How much does Andrea have to contribute each year to have as much as Sarah when they retire? They both earn 5.5% on their savings.