Das geht mit `xshift` für `x `y tick label style`:
\documentclass{standalone}
\usepackage{pgfplots}
\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},
]
\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}
Statt einen von der Schriftgröße abhängigen Wert, kann man natürlich auch einen von der x-Einheit abhängigen Wert verwenden:
\documentclass{standalone}
\usepackage{pgfplots}
\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=2},
]
\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}
Um den Abstand umgekehrt zu vergrößern, verwendet man ggf. negative Werte.
