That was a misnomer, you're right. But that doesn't meaningfully impact my point. An average annual 70% return, some years greater (notably, 2008) and some years lesser, but only a very small number of down quarters or months in the same time frame.
Don't forget to include the preceding 30% drop which reduces both the total returns directly and rate of return as the fund operated over a longer period.
Further, they stopped publishing returns suggesting an even lower long term average.
So, you are looking at a biased subset of a funds returns not total returns which greatly shifts the probability's.