You're absolutely right. Some sectors of agriculture, floriculture for example, have been hit dramatically hard, and some of those workers have transferred to other farming operations. To the best of my knowledge, anybody who has come into the country to work in agriculture, if that position needed to be closed, another job has been found for them.
As for the percentage, just recently I saw some information that 85% of the workers who would normally arrive at this time have arrived, but some growers haven't received any of their workers. There are processing challenges that have made it extremely difficult. I know that in Quebec they use a lot of Guatemalan workers. I believe flights are just starting now, and workers had hoped to be in the fields a few weeks ago. The challenge is great.