In my words. (Possible dollar collapse not taken into account).
- Summer 2015 up to ~$700
- Autumn/Winter 2015 down to ~$400
- Througout 2016 stable as fuck at around ~$400
- Winter/Spring 2017 next rise to ~$2700
- Summer 2017~ $2000
Time and price can deviate from here

(worldwide adoption/use cases found)
- Summer 2018 ~ $14000
- Autumn 2018 ~ $4000
- Summer 2020 ~$67000
- 2021 to 2024 ~ $20000