According to the World Shipping Council (WSC), between 2008 and 2019, there were an average of 1,382 containers lost at sea each year. However, this number is particularly high due to a major shipping accident in 2013, when the MOL Comfort broke in two and sank with its entire cargo of 4,293 containers into the Indian Ocean. 

In recent years, the number of containers lost at sea has fluctuated. For example, the average number of containers lost for the last three years (2020-2022) now stands at 2,301 containers per year, which is a significant rise from the 779 lost on average each year during the previous three years (2017-2019). 

According to the WSC Containers Lost at Sea Report covering 2020-2021, containers lost overboard represent less than 1% of the roughly 226 million containers shipped each year. In the 2020-2021 period, 3,133 containers were lost overboard, compared to 779 in the previous three years. 
It’s worth noting that a few large incidents contributed to the bulk of these losses, such as the One Opus, which lost 1,816 containers northwest of Hawaii.