About the same as now. The prosperity started growing with the government takeover of the central banking functions, and the growth has lasted until now.
I see you've ventured off into Unicorn Land again, here's some actual analysis:
How Modern Sweden Profits from the Success of Its Free-Market History.
The fact is, Progressives gave us Central Banking. Progressives also gave us Income Tax, supposedly to 'help' the worker by 'redistributing' wealth from the rich bankers to the poor workers, in reality, it is used to tax labor in order to redistribute to the Government itself, with a little trickling back to the poor and a lot used to bail out the rich.
The fact is, Central Banking destroyed the German economy.
The fact is, our Central Bankers destroyed our economy, leading to the Great Depression and culminating in World War II.
The fact is, our Central Bankers did it again, and are destroying our economy as we speak. Probably leading us into a Greater Depression and possibly World War III. Or something akin to never-ending-war, which we're already engaged in.
What you see as 'prosperity' is no different than the roaring-20s. It's a Central Banking/Central Planned bubble. Sometimes these bubbles take awhile to play out. Particularly when pigging backing off the industrial revolution and oil exploitation. And while they are playing out, it may seem as if society is becoming prosperous. Progressive rag Salon.com wrote this in 2013:
Hugo Chavez’s economic miracle. One big Progressive unicorn rainbow barf about how "Socialism" (which is to say Statist Authoritarianism) is so wuuuunderful for the 'economy'. You know, because employing violence against morally innocent "Citizens" is 'good for the economy' - or so it then seemed. Business Insider writes this in 2016:
Venezuela is on the brink of a 'political and economic meltdown'.
But, don't you worry, we have an experiment in progress as we speak. Progressive Poster-Child Sweden. That Socialist Mecca in the North. Part of the "Scandinavian Miracle". Oh.... but they ran out of children to sell debt obligations on now didn't they? Gee, what's a Socialistic Mecca going to do? I mean, it takes a lot of work to pay for all the Free-Shit the Progressive politicians promised everyone. Kind of hard to raise a family when you have taxes to pay / free-shit to repay. Ohhhhh.... I know, let's import a bunch of workers. It's sort of a win-win (for business, slum-lords and government, sucks if you're a young Swede looking for a job or a place to rent). But that's okay, because: Free-Shit.
Let's see if we aren't reading an article with a title that reads something along the lines of this:
Sweden is on the brink of a 'political and economic meltdown'. And there you'll be, claiming Sweden isn't a "Real" Socialistic country. Nope, no True Scotsmen around there here parts....
LOL