Whether you’re busy with showings or taking the day off, your email marketing should be working on Sunday. According to an analysis of 368 million messages by email software firm Yesware, emails sent on Sunday saw the highest number of replies per sent message.

This finding confirms a previous study of 500,000 emails that showed Sunday saw the least amount of inbox competition (i.e., the fewest emails being sent). According to the previous study, open and reply rates are highest during the weekend. In the new study, the lowest ratio of replies to sent messages was on Fridays.

A tool that lets you schedule emails from a personal account, such as Boomerang if you use Gmail, can allow you to grab prospects’ and clients’ attention when there’s the least amount of inbox competition.