You are talking about nominal turnout.  It was 57%.
However, nominal turnout is almost irrelevant.
.
B.C. has 4.770 m people
81% (3.864 m) are eligible to vote.
81.7% (3.157 m) registered.
56.9 % (1.797 m) voted.
.
True or absolute turnout was 1.797m/3.864m = 46.5 %, an all-time low.
(81.7% registration was also an all-time low.  Prior to voter ID, 90 - 92% was typical.)
.
In 2013 it was 47.4%.
In 2005 (before voter ID) it was 58%.
.
Vote suppression has many levels.
.
People are discouraged from registering;
Those registered are discouraged from voting;
Low information voters are encouraged to waste their votes, or to behave irresponsibly or short-sightedly.
.
These phenomena have been heavily studied.
.
At the end of the day, in the era of abuse of big data and narrow-cast online browser tracking and targeting, nominal turnout is a weak trend-revealing indicator, because it is a secondary or derivative indicator.
.
Absolute turnout, by contrast, is virtually always determinative.