Question

What does it mean if a nation has a high dependency rate

Answer 1

It means the nation has a large number of children, whose families must provide for them

Answer 2

If a nation has a high dependency rate, it means that the nation has a large number of children, whose families must provide for them. But this isn't a complete answer really - it isn't only children who are  dependent, but also the elderly, the sick, and people with disabilities.