Why Does the Work Force Have to Be Replenished?

The Post featured an interesting piece by William Frey which contrasts the ethnic and racial composition of the baby boom cohorts with those under age 30. At one point the piece tells readers:

"Between now and 2030, there will be an absolute decline of 10 million (mostly baby-boom) whites from the ranks of our working-age population.

Those ranks can be replenished only by the growing minority youth population. Much of this growth will occur because of births, regardless of immigration trends....