Evidence of labor supply, or worker gap in a country includes (1) an absolute decline in working age population and (2) an increase in the aged population compared to the working age population. A labor supply gap in a country can be solved by either automation and/or immigration.
From the Center for Global Development:
For the period 2015 to 2050, prime working-age populations of OECD (
Organisation for Economic Co-operation and Development) countries will shrink by more than 92 million people while there will be nearly 1.4 billion new working-age people in developing countries.
In high income countries, the population aged 20-64 will be 46 million smaller in 2050 than 2020. In upper-middle income countries there will be 85 million fewer potential workers.
The “dependency” ratio for a country is the number of young and old people not usually in the labor force compared to the working age population (say, 20 through 64 years). 2020-2050 will see rapidly rising dependency ratios in those countries driven by aging. The number of people aged 65 or older expressed as a percentage of the population aged 20 to 64 will climb from 31 percent to 50 percent in high-income countries between 2020 and 2050, and from 17 percent to 40 percent in upper-middle income economies
The ‘worker gap’ adds up to 202 million people in high income countries and 465 million in upper-middle income countries. China alone will see a worker gap of 384 million connected with a working age population that will shrink by 160 million between 2020 and 2050 as the population of retirement-age workers expands.