documentclass[a4paper]{article}

usepackage{tikz}
usetikzlibrary{fit,calc,positioning}
usetikzlibrary{shapes.geometric}
usepackage{ifthen}

definecolor{textgray}{HTML}{525252}

edefmycolorr{red} edefmycolory{yellow} edefmycolorg{green}

begin{document}

%% Set satisfactory value  newcounter{satisfactoryvalue}
setcounter{satisfactoryvalue}{85}  %% here place percentage
newcommand{myfactor}{0.85} %% here place scaling factor

newcommand{scaletomyfactor}[1]{%
    csname rem@ptexpandafterendcsnamethedimexpr #1dimexprmyfactor ptrelaxrelax }

newlength{duz} setlength{duz}{16cm}


ifthenelse{value{satisfactoryvalue}<33}{edefmycolorf{mycolorr}setcounter}{ifthenelse{value{satisfactoryvalue}<66}{edefmycolorf{mycolory}}{edefmycolorf{mycolorg}}}

begin{center} begin{tikzpicture} node at (0,0) [draw, rectangle,
minimum width=duz, minimum height=1.5cm, textgray] (r1) {}; node at
(r1) [fill, rectangle, mycolorf, minimum
width=scaletomyfactor{myfactor}duz,  minimum height=1.5cm] (r2) {};
end{tikzpicture} end{center}

end{document}