Most concerns center around several related issues: an ageing population, growing life expectancy and immigrant flow.
The figure was reached on the basis of a projected immigrant flow of 200,000 a year.
Again this immigrant flow was at least 80% male and the demand for female Japanese immigrants almost immediately arose.
Pending legislation will add only more ways to increase the size of the annual immigrant flow.
The immigrant flow started with the abolition of slavery in 1888, which required new sources of labor.
They say economic conditions in European nations, including Ireland, did not create the heavy immigrant flow from other parts of the world in recent decades.
He urged them to concentrate on workplace safety, wage increases and regulating the immigrant flow.
Although immigrant flows are not broken out in the census data, the effects of more than 15 years of steady immigration can be seen.
These immigration laws were intentional efforts to control the composition of immigrant flow into the United States.
The preponderance of the immigrant flow has been into urban areas, especially to central cities.