Avec pgfplots et la librairie `fillbetween`:
\documentclass[tikz]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.10}
\usepgfplotslibrary{fillbetween}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
axis lines=left,
domain=0:10,
ymin=10,
enlargelimits=false,
clip=false,
grid=both,
grid style={line width=.1pt, draw=gray!10},
major grid style={line width=.2pt,draw=gray!50}]
\addplot[red,name path=B] table {Russie-TM.txt};
\addplot[black,name path=A] table {Russie-TN.txt};
\addplot[blue!50] fill between[of=A and B];
\end{axis}
\end{tikzpicture}
\end{document}
