Amazon Prime Day 2021 kicked off at midnight on June 21 and runs until 11:59 p.m. on June 22. The annual two-day sale event is one of the busiest shopping periods for the company. Hundreds of thousands of goods are on sale, which results in a feeding frenzy from customers.

Every year since Prime Day kicked off in 2015, sales have steadily risen for the event. But this year’s Prime Day is predicted to be the biggest in terms of sales revenue yet. According to marketing research firm eMarketer, Amazon Prime Day 2021 is set to bring in $11.79 billion in sales for Amazon. That’s nearly $2 billion more than the $9.91 billion Amazon brought in in 2020. Here’s how eMarketer says those numbers stack up since 2016:

• Prime Day 2016: $1.5 billion in sales
• Prime Day 2017: $2.47 billion in sales
• Prime Day 2018: $4.13 billion in sales
• Prime Day 2019: $6.93 billion in sales
• Prime Day 2020: $9.91 billion in sales
• Prime Day 2021: $11.79 billion in sales

However, as eMarketer notes, the year-over-year growth of Amazon Prime Days sales is slowing rapidly. Between 2016 and 2019, Prime Day sales grew at an average rate of 66.6% per year. In 2020 Prime Day sales only grew 43% YOY, and in 2021 Prime Day sales are set to grow only 19% YOY. Still, it’s hard to argue with an extra almost $2 billion in sales over two days. And if you’re not an Amazon fan, there are other Prime Day alternatives where you can shop great sales this week.