There is a quota for employment-based green cards (typically 140k/year). The number of applicants that apply each year is larger than the quota. So every year t

There is a quota for employment-based green cards (typically 140k/year). The number of applicants that apply each year is larger than the quota. So every year the total number of people who have applied but cannot be approved due to the quota gets larger. Because of the per-country limit of 7%, these queuing dynamics generally only affect people from countries with large number of applications (India, China). But sometimes there will be a backlog for all countries. The current forecast is that there will be a backlog in 2023 in the EB2 category for all countries.