--- a/handouts/ho03.tex	Thu Oct 23 00:45:21 2014 +0100
+++ b/handouts/ho03.tex	Thu Oct 23 11:30:21 2014 +0100
@@ -17,31 +17,42 @@
 very relevant even today since there are many legacy systems
 out there and also many modern embedded systems often do not
 take any precautions to prevent such attacks. The plot below shows
-the percentage of buffer overflow attacks w.r.t.~all attacks.
-The data is taken from the US National Vulnerability Database.
+the percentage of buffer overflow attacks listed in the US National 
+Vulnerability Database.\footnote{Search for ``Buffer errors'' at 
+\url{http://web.nvd.nist.gov/view/vuln/statistics}.}
 
 \begin{center}
 \begin{tikzpicture}
 \begin{axis}[
     xlabel={year},
     ylabel={\% of total attacks},
+    ylabel style={yshift=-1em},
     enlargelimits=false,
-    xtick={1997,1999,...,2014},
+    xtick={1997,1998,2000,...,2014},
+    xmin=1996.5,
     xmax=2015,
-    ymax=20,
+    ymax=21,
     ytick={0,2,...,20},
     scaled ticks=false,
     axis lines=left,
-    width=9cm,
+    width=12cm,
     height=5cm,
     ybar,
-    x tick label style={font=\footnotesize}]
+    nodes near coords=
+     {\footnotesize
+      $\pgfmathprintnumber[fixed,fixed zerofill,precision=1,use comma]{\pgfkeysvalueof{/data point/y}}$},
+    x tick label style={font=\footnotesize,/pgf/number format/1000 sep={}}]
 \addplot
   table [x=Year,y=Percentage] {bufferoverflows.data};
 \end{axis}
 \end{tikzpicture}
 \end{center}
 
+\noindent
+This statistics seems to indicate that in the last five years the
+number of buffer overflow attacks is around 10\% of all attacks
+(whereby the absolute numbers of attacks seem to grow each year).
+
 
 To understand how buffer overflow attacks work, we have to have
 a look at how computers work ``under the hood'' (on the