\documentclass[12pt,a4paper]{article}  
 \usepackage{color,setspace} 
\definecolor{gray100}{gray}{1.0}
\definecolor{gray90}{gray}{0.90}
\definecolor{gray80}{gray}{0.80}
\definecolor{gray70}{gray}{0.70}
\definecolor{gray60}{gray}{0.60}
\definecolor{gray50}{gray}{0.50}
\definecolor{gray40}{gray}{0.40}
\definecolor{gray30}{gray}{0.30}
\definecolor{gray20}{gray}{0.20}
\definecolor{gray10}{gray}{0.10}
\definecolor{gray0}{gray}{0}

\usepackage{array}% in the preamble
\begin{document}  
\begin{spacing}{0.7}
\noindent
{\scriptsize 90}\textcolor{gray90}{\rule{10mm}{3mm}}\newline
{\scriptsize 80}\textcolor{gray80}{\rule{10mm}{3mm}}\newline
{\scriptsize 70}\textcolor{gray70}{\rule{10mm}{3mm}}\newline
{\scriptsize 60}\textcolor{gray60}{\rule{10mm}{3mm}}\newline
{\scriptsize 50}\textcolor{gray50}{\rule{10mm}{3mm}}\newline
{\scriptsize 40}\textcolor{gray40}{\rule{10mm}{3mm}}\newline
{\scriptsize 30}\textcolor{gray30}{\rule{10mm}{3mm}}\newline
{\scriptsize 20}\textcolor{gray20}{\rule{10mm}{3mm}}\newline
{\scriptsize 10}\textcolor{gray10}{\rule{10mm}{3mm}}\newline
\end{spacing}
\end{document}
