I made a chart - goes back as far as Bitstamp has been trading Bitcoin. Gold is the black bars and Bitcoin is the orange line

My view of the drivers - currency controls in China, India and Venezuela. The ETF approval is pretty uncertain. I found someone prepared to put a number on it 10 to 15% https://vinnylingham.com/preventing-another-bitcoin-bubble-98dee44e2c7c#.iep9uqk4w