2017 was 4th best year for Bitcoin after 2010, 2013 and 2011. You see all beside year 2014 were positive.
2010 $0.003 +10000%
2011 $0.3 +1566%
2012 $5 +160%
2013 $13 +5823%
2014 $770 -59%
2015 $316 +36%
2016 $430 +128%
2017 $980 +1286%
2018 $13585
2017 gave bitcoin it's break. It's stability and the quick growth on the price chart made bitcoin a very prospective investment. It even helped altcoins to grow as well. Increase in people's support helped bitcoin tackle volatility. It will mostly cross 30 k by the end of the first half of 2018.