With respect, this is not quite correct.
If you are self employed, the Social Security tax paid was seven percent in the '70s, eight percent in the early '80s, and about twelve percent since then.
If you worked for a salary, the maximum rate was (approximately) five percent in the '70s and slightly over six percent since then. You really can't count the employer contributions, as absent the SS program there is no way to know whether those funds would have been added to your take home pay or not.
Without knowing your income history over the last couple of decades, it would be impossible to know whether those SS taxes would have grown into a multi-million sum or not. But most people do tend to overestimate the total amount paid by them into SS and Medicare (even considering investing those funds at a conservative rate) by comparison with the amount they have received., or actuarially are scheduled to receive.
Thirty years ago, tiny Galveston opted out of the entire Social Security system for its county employees and introduced private accounts.
It was the brainchild of a county judge, Ray Holbrook, and a few other officials, who took a good look at the parlous state of Social Security in the late 1970s and came up with an "Alternate Plan" of privately managed personal accounts they believed would outperform the public model. An opt-out clause in the original 1935 law (since shut) let them try something different.
How did they do? Three decades later, Galveston County employees take home pensions with nearly a 7% average annual return compounded over 30 years.
By contrast, Social Security recipients get a 1% to 2% return and newer workers will get even less. So Galveston's retirement checks are about four times the size of Social Security and come with life insurance, too.