The tendency of the profit ratio to fall

One of Korean economy professor, SungJin Jung, claimed that the profit ratio in America industry has tendency of the ratio of profit to fall, which is one of the famous Marx's theory.
In his article he was using America government data, which is open data to public.

The diagram he was using is here:The data is from one of the government web site: http://www.bea.gov
Non- financial corporate sector ratio = National Income and Product Accounts, Table 1.14. line 24(net operating surplus)-line 26 (business current transfer payment) / Fixed Asset Table, Table 4.1. line 28(non-financial)

Considering the non-financial corporate sector ratio as profit ratio, the point of this article is that the diagram indicates the profit ratio has tendency to fall.

I wanted to get the diagram by myself, so I made it; this means everybody can draw the diagram.
There is two reason why the diagrams are different.
One is that the web site revised the data after the article is written. The other reason is that I included two more years: 2006, and 2007. And the government web site doesn't have data before 1930.
You can see the Trend line is declining.

I, however, found one interesting point.
Two of them averaging the data by 5 years.
But if I just use raw data, which is year by year, then I get different diagram here:
If you click the diagram above, you can see bigger one.
The new line looks like *flat*, not declining.
The reason is the new diagram is wider.
If I make it narrow, then you can see the same declining line like this:
In brief, although different analysis way shows different diagram, it is definitely not increasing. It is opposite result from the opinions of some of famous leftists who claims that the falling tendency problem is overcame.

In addition, even though we can say it is declining, it does not look significant.