Wie kann ich den Abstand von ylabel in pgfplots zur y-Achse verringern?

\documentclass{standalone}

\usepackage{pgfplots}
\pgfplotsset{compat=newest}

\begin{document}
\begin{tikzpicture}
  \begin{axis}[
    height=7cm,
    width=\textwidth,
    ybar,
    xmin = 1984, xmax = 2015,
    ymin = 0, ymax = 2,
    xtick={1985,...,2015},
    x tick label style={rotate=90, anchor=east, /pgf/number format/1000 sep=},
    ylabel={Number of failure},
    ytick={0,...,2},
    y tick label style={xshift=.2em},
    y label style={yshift=-.5em},
    ]
  \addplot coordinates {
    (1985, 0)
    (1986, 0)
    (1987, 0)
    (1988, 0)
    (1989, 0)
    (1990, 0)
    (1991, 0)
    (1992, 0)
    (1993, 0)
    (1994, 0)
    (1995, 0)
    (1996, 0)
    (1997, 0)
    (1998, 0)
    (1999, 0)
    (2000, 0)
    (2001, 0)
    (2002, 0)
    (2003, 0)
    (2004, 0)
    (2005, 0)
    (2006, 0)
    (2007, 0)
    (2008, 0)
    (2009, 0)
    (2010, 0)
    (2011, 0)
    (2012, 0)
    (2013, 0)
    (2014, 0)
    (2015, 0)
    (2012, 1)
  };
    \end{axis}
  \end{tikzpicture}
\end{document}