The ever-growing surplus value

I'm borrowing here a graph appeared at Naked Capitalism (data for the USA but it could be anywhere):

 

The implications are obvious: capitalists have been taking an ever growing share of the produced wealth since c. 1972. Previously, in what some have described as the period of "generous capitalism" (caused by the Cold War and fear of socialist revolutions) surplus value (the share of production appropriated by capitalists as manager class of the economy) was more or less stable, but since the 1970s it has grown steadily up to more than double, while real wages have remained stable. 

Wages are the share of production kept by producers, workers. But beware: salaries have remained stable but the share of wealth retained by producers has declined very sharply. 

This is how Capitalism works normally in fact. Marx explained it in Das Kapital with the example of the pin factory, in which vast improvements in technology and organization of production (~ productivity) led only to loss of jobs, not any improvement to the conditions of workers but exactly the opposite. 

Only radical and global class struggle caused a parenthesis in this natural tendency of Capitalism: the post-war decades of relatively shared affluence, which marked a generation that is now dying out.

But for all other generations of workers this is just the normal. And that is why Communism is extremely necessary and urgent.