218 ANNUAL REPORT SMITHSONIAN INSTITUTION, 195 7 



2400 



2000 



1600 



US 



STANDARD 1200 

 OF LIVING 



800 



I 



NUMBER 



OF 

 PEOPLE 



400 



1800 



1850 1900 



YEAR 



1950 



Figure 5. 



r\ 



!C 



— — DISTRIBUTION OF ABILITIES 



U S INCOME 



EARLY MARXIAN 



PROBABLE CURRENT 



MARXIAN 



ABILITIES 

 INCOME* 



Figure 6. 



