How can 75% of a population receive a UNIVERSAL basic income? UBI is by definition every single person.
UBI is a bandage which covers (and ignores) a much larger problem. It seems like a good idea on the surface, but fails to fix the problem that causes the need for it: income inequality.
A better solution is paying people to attend university. Society makes the investment of cash, and later receives the benefit of well-educated citizens. The student makes the investment of time and energy, and receives the benefit of the ability to pay their rent, child care and food. Once sufficiently educated in a subject of the student’s choosing, he or she may start a company, advance science, or apply their skills as an employee. Educated citizens are far more able to solve their own dilemmas, requiring fewer social services (e.g. police, fire, medical, or rent assistance.)