From the wikipedia article on Swedish iron mining during WW2, there are a lot of uncited claims. I'll quote the most outstanding of them here:
In the year before the war, Germany received 22 million tons of iron ore from various foreign sources. Although it was able to produce around 10m tons of its own iron ore each year, it was of low grade quality and needed to be mixed with high grade material from other countries such as Sweden, which annually supplied it with 9 million tons
Grand Admiral Raeder, head of the German navy, declared that it would be "utterly impossible to make war should the navy not be able to secure the supplies of iron-ore from Sweden".
Any truth to these?
Apparently the British thought it critical enough to try to interdict it, but never got much of a chance after Germany controlled Norway (1940 May onwards). Still, if it was this critical, you'd think there be sources. Just how dependent was Nazi Germany on Swedish iron ore? Would the Wermacht really grind to a halt without it?
I'm looking for documented numbers regarding this.