bitcoin slowly went down this year, from almost 20k USD last December and went down at a significant price
what might be the reason why bitcoin's price is going down?
what are the major things that can greatly influence bitcoin?
answers would be fully appreciated

Cryptocurrency and bitcoin are very much sensational in 2017. There were a lot of scams that this HYIP decided to deceive people. ICO which did not come to the exchange and many other schemes with hacking of the exchange and theft of bitcoins. A lot of stories turned away from young and promising investors.