BTC dip compared to earlier years

Cryptocurrencies have had a rough week: the value of bitcoin plunged to a mere 50 percent of its 2017 peak, and other currencies, such as Ethereum, Ripple, and Litecoin have seen double-digit losses compared to their heights from last year.There is a lot of panic in the market. People are selling to try and get the hell out of there.
Markercap differences compared:
4.12.2014 = 15,9 billion $
18.12.2014 = 6,26 billion $
2014 (1) difference = -60,63%
6.1.2014 = 13,7 billion $
11.4.2014 = 5,6 billion $
2014 (2) difference = -59,12%
1.1.2015 = 5,43 billion $
14.1.2015= 3 billion $
2015 difference = -44,75%
5.1.2016 = 5 billion $
12.1.2016 = 12 billion $
2016 difference -36,36%
5.1.2017 = 21,8 billion $
12.1.2017 = 14,6 billion $
2017 difference = -33,03%
8.1.2018 = 833 billion $
17.1.2018 = 421,8 billion $
2018 difference = -49,36%