If you are going to use such figures as a means to negate my comment, the least you could do is take into consideration the other factors that your chart does not recognize.
Your chart ranges from 1950-2010; let's examine the labor market from 1944 - 1950 for some background work.
The labor force came off of record low unemployment in 1944 (1.2%) and by October 1949 a minor recession pushed unemployment up to 7.9%, yet by November 1950 labor markets had stabilized (4.2% unemployment). All the while, the top marginal tax rate was roughly 88.4%!
You are probably thinking, "see, high taxes on the rich do not discourage employment growth!". What you are not taking into consideration is the composition of the said tax rates. Prior to 1942, the top marginal tax rate applied for people making over $5,000,000.00 annually (via income) which if we were to factor for inflation using the CPI it would be equivalent to around $66,000,000.00 or via the GDP deflator it would be approximately $55,300,000.00 in terms of 2010 dollars.
Following WWII, the top bracket fell to $200,000.00 (about $2,250,000 in 2010 dollars) which brings me to effective taxation.
Because i am totally unwilling to mine for effective tax data pre 1979 (of which the top rate was 70%), the numbers will not apply to the '40's '50's, 60's up to 1979, but the logic is identical and so it makes very little difference.
The effective tax rate measuring all quintiles in 1979 was only 22%, while the effective rate for the top 1% of income earners was 37.4%. How can this be? Marginal tax rates work through brackets. Let's assume there were only two brackets, 25% and 50% for incomes over $100,000.00 and $1,000,000.00 respectively. Anyone earning less than $100k pays zero in taxes. Anyone earning between $100k and $999k pays only 25% and a person earning exactly $1 million pays only 25.000005%. An income of $10,000,000.00 (in this scenario) only pays 47.5% which would be their effective tax rate. The more the brackets and closer the partitions, the lower all effective tax rates become.
Which is why there is a difference between marginal rates and effective (what you pay) rates.
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How does your chart prove that raising taxes when unemployment is @ 9.2% will be labor market neutral?
Answer: It does not!