Throw in Obama term thus far and real data instead of projected data and it shows a different picture....one that is just as worthless as this one.
Also, if you draw a trendline starting from 1950 to the present it actually has a downward slope, negating the argument of governemnt growth over the period.
We should look at external factors here and consider what if's. What if Reagan didn't have to fight the cold war and arms race? What if Clinton did? What if Reagan and Clinton switched places in history? What if Kerry had won in 2000 instead of Bush? While the president can affect the economy, deficits, etc...external factors carry a much heavier hand. As a rule, the president is at the mercy of the circumstances of his time. Personally, I don't assign too much blame to deficits under Reagan/Bush/Obama...and I don't give too much credit for successes under Kennedy and Nixon.