This is a nonsense statistic. Of course apprentices have vastly higher employment. Apprentices would normally only be taken on with a view to being retained at the end, and they usually have a role to play in the organisation during their apprenticeship. It would be mad to train an apprentice in the first place if you didn't have a role for them at the end - otherwise, why do it?
Usually, the problem is the opposite - a firm trains an apprentice, and upon completion, another firm comes in and poaches them without having to pay to train them.