\documentclass{standalone}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{xcolor}
\usepackage[margin=1in]{geometry}
\usepackage{pgfplots}
\usepgfplotslibrary{groupplots}
\pgfplotsset{compat=newest}
% define colors
\newcommand{\colorI}{cyan}
\newcommand{\colorIII}{magenta}
\newcommand{\colorII}{yellow}
\newcommand{\colorIV}{green}
\begin{document}
% set the style for all 4 plots
\pgfplotsset{
every axis plot/.style={line width=0.5pt},
/pgf/bar width=8pt, % set the width of the bars
every axis post/.append style={xmin=0, xmax=10, ymin=0, ymax=1.5, % set the limits on both axis
xticklabel={$\pgfmathprintnumber{\tick}\%$}, % since we want to read the numbers from our tables and add the percentage sign
enlarge x limits={abs=2.5}, % enlarge the x-axis
}
}
% read the tables from text files
\pgfplotstableread{data/tableA.txt}{\tableA}
\pgfplotstableread{data/tableB.txt}{\tableB}
\pgfplotstableread{data/tableC.txt}{\tableC}
\pgfplotstableread{data/tableD.txt}{\tableD}
\begin{tikzpicture}
\begin{groupplot}[
group style={
{group size=2 by 2}}, height=6cm, width=.5\textwidth,legend style={
transpose legend,
legend columns=0,
% draw=none, % if you want to hide the frame around legend
/tikz/every even column/.append style={column sep=5pt}},
ybar,
xtick=data,
tickpos=left,
ytick align=inside,
xtick align=inside,
x tick label style={ align=center},
legend image code/.code={\draw (0cm,-0.2cm) rectangle (0.2cm,0.25cm);},
]
\nextgroupplot[%title={Title},
legend to name=grouplegend,
ylabel={Label},
]
\draw[ystep=.25,xstep=-1,gray,very thin,dashed] (-5,0) grid (15,1.5); % grey dashed lines to help reading the chart; the coordinates are set manually
\addplot[draw=black,fill=\colorI,error bars/.cd,y dir=both,y explicit] % change the colors if you wish
table[x index=0,y index=1,y error plus index=2,y error minus index=2] {\tableA}; % change the indices if necessary
\addlegendentry{A} % change the legend entry
\addplot[draw=black,fill=\colorII,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=3,y error plus index=4,y error minus index=4] {\tableA};
\addlegendentry{B}
\addplot[draw=black,fill=\colorIII,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=5,y error plus index=6,y error minus index=6] {\tableA};
\addlegendentry{C}
\addplot[draw=black,fill=\colorIV,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=7,y error plus index=8,y error minus index=8] {\tableA};
\addlegendentry{D}
\nextgroupplot%[title=Title]
\draw[ystep=.25,xstep=-1,gray,very thin,dashed] (-5,0) grid (15,1.5);
\addplot[draw=black,fill=\colorI,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=1,y error plus index=2,y error minus index=2] {\tableB};
\addplot[draw=black,fill=\colorII,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=3,y error plus index=4,y error minus index=4] {\tableB};
\addplot[draw=black,fill=\colorIII,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=5,y error plus index=6,y error minus index=6] {\tableB};
\addplot[draw=black,fill=\colorIV,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=7,y error plus index=8,y error minus index=8] {\tableB};
\nextgroupplot[yshift=-2\pgfkeysvalueof{/pgfplots/every axis title shift},
ylabel={Label}]
\draw[ystep=.25,xstep=-1,gray,very thin,dashed] (-5,0) grid (15,1.5);
\addplot[draw=black,fill=\colorI,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=1,y error plus index=2,y error minus index=2] {\tableC};
\addplot[draw=black,fill=\colorII,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=3,y error plus index=4,y error minus index=4] {\tableC};
\addplot[draw=black,fill=\colorIII,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=5,y error plus index=6,y error minus index=6] {\tableC};
\addplot[draw=black,fill=\colorIV,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=7,y error plus index=8,y error minus index=8] {\tableC};
\nextgroupplot[yshift=-2\pgfkeysvalueof{/pgfplots/every axis title shift}]
\draw[ystep=.25,xstep=-1,gray,very thin,dashed] (-5,0) grid (15,1.5);
\addplot[draw=black,fill=\colorI,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=1,y error plus index=2,y error minus index=2] {\tableD};
\addplot[draw=black,fill=\colorII,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=3,y error plus index=4,y error minus index=4] {\tableD};
\addplot[draw=black,fill=\colorIII,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=5,y error plus index=6,y error minus index=6] {\tableD};
\addplot[draw=black,fill=\colorIV,error bars/.cd,y dir=both,y explicit]
table[x index=0,y index=7,y error plus index=8,y error minus index=8] {\tableD};
\end{groupplot}
% add a legend
\node at ($(group c1r2.south)!0.5!(group c2r2.south)$) [below, yshift=-4\pgfkeysvalueof{/pgfplots/every axis title shift}]{\ref{grouplegend}};
% add captions
\node at ([below,yshift=-2\pgfkeysvalueof{/pgfplots/every axis title shift}]group c1r1.south) {
(a) Caption A % change the caption
};
\node at ([below,yshift=-2\pgfkeysvalueof{/pgfplots/every axis title shift}]group c2r1.south) {
(b) Caption B
};
\node at ([below,yshift=-2\pgfkeysvalueof{/pgfplots/every axis title shift}]group c1r2.south) {
(c) Caption C
};
\node at ([below,yshift=-2\pgfkeysvalueof{/pgfplots/every axis title shift}]group c2r2.south) {
(d) Caption D
};
\end{tikzpicture}
\end{document}
