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
Based on net growth and not percentage statistics, 2017 has clearly been the best year for Bitcoin with an opening at the three figure mark and closing at much over the five figure mark. Pretty sure the whole world of speculators were talking about $5k~ for the first 6 months of the year and Bitcoin breached all expectations reaching to as much as $20k.