Is that it was a bipartisan agreement between the five biggest political parties under the leadership of the Socialdemocrats that made the scheme possible.
The funded part is only a small part of the total pension, 2,5 percent of your gross income which is automatically put into a 401k-like platform with about 700 investment funds to choose from.
The total first pillar pension is 18,5 of ones gross earnings. 16 percent is managed by the government.
AND for those who don´t make enough money to reach a certain pension level (single mothers, women who have stayed home raising their children, i.e. have not worked enough, or low income earners or basically anyone else) will receive a top up or "guarantee pension" by the government to guarantee that no one falls between the cracks.
The system was launched in 2000 (worst possible scenario) and a lot of people are angry as their savings are in the red.
Now a government committee is looking over the scheme to suggest improvements.
To this one has to remember and add that almost everyone has a occupational second pillar pension through their collective union agreements. And universal health care, etc etc.
It would be very difficult and dangerous to compare the Swedish experience and the US proposal.
If anyone is interested to learn more about the Swedish Social Insurance (Pensions, medi- and dental care, family and employment parts) if republicans ever tries to compare the two:
http://www.forsakringskassan.se/sprak/eng/