pgfplots - How can I define the bar width for a xbar plot?

Question

I found the key bar width on page 82 in the manual.

However, when I use it:

! Package pgfkeys Error: I do not know the key '/pgfplots/bar width', to which you passed '5pt', and I am going to ignore it. Perhaps you misspelled it.

Is there something (hopefully not so obvious) that I missed?

MWE

\documentclass[
a4paper
]{scrartcl}

\usepackage{
amsmath,
tikz,
pgfplots,
pgfplotstable,
}

\usepackage{lmodern}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

\usepgfplotslibrary{groupplots}


\pgfplotstableread[col sep=comma]{
Process,ValueA,ValueB
1,66,70
2,66,40
3,24,20
4,52,60
5,64,30
6,12,10
}{\tableabcdef}

\begin{document}
\begin{center}
\begin{tikzpicture}[font=\small]
\begin{groupplot}[
group style={
    group size=2 by 1, %2 cols 1 rows
    horizontal sep=1cm,
    %horizontal sep=2.5cm,
%   vertical sep=2.25cm,
    ylabels at=edge left,
    yticklabels at=edge left,
},
%
width=5cm,
height=7cm,
%
xlabel={Force in N},
ylabel={Process \#},
%
xbar,
bar width=5pt,
%
ytick=data,
nodes near coords,
nodes near coords align={right}
]
\nextgroupplot
\addplot+ table [x=ValueA, y=Process] {\tableabcdef};
\nextgroupplot
\addplot+ table [x=ValueB, y=Process] {\tableabcdef};
\end{groupplot}
\end{tikzpicture}
\end{center}
\end{document}

Answer 1

Use

/pgf/bar width=5pt,% bar width

Additionally, I would add the options

xmin=0,% minimum x value
enlarge x limits={abs={1.5em},upper},% space for nodes near coords

Code:

\documentclass[margin=10pt]{standalone}
\usepackage{lmodern}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{pgfplots,pgfplotstable}
\usepgfplotslibrary{groupplots}
\pgfplotsset{compat=1.10}

\begin{filecontents*}{force-stats.txt}
Process,ValueA,ValueB
1,66,70
2,66,40
3,24,20
4,52,60
5,64,30
6,12,10
\end{filecontents*}
\pgfplotstableread[col sep=comma]{force-stats.txt}{\tableabcdef}

\begin{document}
\begin{tikzpicture}[font=\small]
  \begin{groupplot}[
      group style={
          group size=2 by 1, %2 cols 1 rows
          horizontal sep=1cm,
          %horizontal sep=2.5cm,
          %vertical sep=2.25cm,
          ylabels at=edge left,
          yticklabels at=edge left,
      },
      %
      width=5cm,
      height=7cm,
      %
      xlabel={Force in N},
      ylabel={Process \#},
      %
      xbar,
      /pgf/bar width=5pt,% bar width
      %
      xmin=0,% minimum x value
      enlarge x limits={abs={1.5em},upper},% space for nodes near coords
      %
      ytick=data,
      nodes near coords,
      nodes near coords align={right},
    ]
    \nextgroupplot
    \addplot+ table [x=ValueA, y=Process,col sep=comma] {\tableabcdef};
    \nextgroupplot
    \addplot+ table [x=ValueB, y=Process,col sep=comma] {\tableabcdef};
  \end{groupplot}
\end{tikzpicture}
\end{document}

Note that I have used filecontents* instead of filecontents.