[mrb]

«isn't significant proof of decline, although since it's 2 of 5, a 40% decline seems notable to me»

Any percentage value is irrelevant because a change of ±2 among 500 retailers is statistically insignificant. If it was ±20 it would be significant.

What if we went from 1 to 2 accepting BTC, would you say "acceptance went up 50% among top 500 retailers?" It would be highly misleading and improper to report it as such.

[wpietri]

Taking the one bit you want to argue with but ignoring the meat of my point certainly isn't something I'm finding useful. I'll take my leave here.

[saalweachter]

If they went from 1 to 2 accepting BTC, I would say "acceptance went up 100%".