Define a new command to insert a pie slice:

\newcommand{\slice}[4]{
  \pgfmathparse{0.5*#1+0.5*#2}
  \let\midangle\pgfmathresult

  % slice
  \draw[thick,fill=black!10] (0,0) -- (#1:1) arc (#1:#2:1) -- cycle;

  % outer label
  \node[label=\midangle:#4] at (\midangle:1) {};

  % inner label
  \pgfmathparse{min((#2-#1-10)/110*(-0.3),0)}
  \let\temp\pgfmathresult
  \pgfmathparse{max(\temp,-0.5) + 0.8}
  \let\innerpos\pgfmathresult
  \node at (\midangle:\innerpos) {#3};
}

Then define the slices in the order you want to have them and with the percentages and labels. You can start at a different point in the circle by setting the counter ‘d’ to a different value before the loop, e.g. \setcounter{d}{25}.

\begin{tikzpicture}[scale=3]
\newcounter{c}
\newcounter{d}
\foreach \p/\t in {66/, 17/Equative, 10/Difference, 7/}
  {
    \setcounter{c}{\value{d}}
    \addtocounter{d}{\p}
    \slice{\thec/100*360}
          {\thed/100*360}
          { \small \p\%}{\t}
  }
  \node[label=0.5:Ranked] at (1,0.6) {};
  \node[label=0.5:Superlative] at (1,-0.3) {};
\end{tikzpicture}

I didn’t like the automatic placement of two labels, that is why I gave ‘Ranked’ and ‘Superlative’ an empty label in the loop and placed them by hand later on.

The original is from Texample, uploaded by Robert Vollmert.