800%

Yes, It Is a Ponzi Scheme - Michael Tanner - National Review Online: "Of course, Social Security and Ponzi schemes are not perfectly analogous. Ponzi, after all, had to rely on what people were willing to voluntarily invest with him. Once he couldn’t convince enough new investors to join his scheme, it collapsed. Social Security, on the other hand, can rely on the power of the government to tax. As the shrinking number of workers paying into the system makes it harder to continue to sustain benefits, the government can just force young people to pay even more into the system.

In fact, Social Security taxes have been raised some 40 times since the program began. The initial Social Security tax was 2 percent (split between the employer and employee), capped at $3,000 of earnings. That made for a maximum tax of $60. Today, the tax is 12.4 percent, capped at $106,800, for a maximum tax of $13,234. Even adjusting for inflation, that represents more than an 800 percent increase."