I only periodically (every couple of months) bet only a few dollars worth of bitcoin, so 0.001~0.005 at a time.  I was really surprised to see in your poll that the lowest option to choose was "< 0.1 BTC" which is about $60 right now.  After choosing that though, it looks like most people bet under 0.1 BTC.  I wonder how many of them bet as low as I do, around 0.001~0.005 range.  Maybe you should do another poll and include some smaller ranges in your choices to see exactly how much that group of "< 0.1 BTC" are actually betting.  I would be curious to find out at least.