

    \filetitle{pct}{Percent rate of change}{tseries/pct}

	\paragraph{Syntax}

\begin{verbatim}
X = pct(X)
X = pct(X,K,...)
\end{verbatim}

\paragraph{Input arguments}

\begin{itemize}
\item
  \texttt{X} {[} tseries {]} - Input tseries object.
\item
  \texttt{K} {[} numeric {]} - Time shift over which the rate of change
  will be computed, i.e.~between time t and t+k; if not specified
  \texttt{K} will be set to \texttt{-1}.
\end{itemize}

\paragraph{Output arguments}

\begin{itemize}
\itemsep1pt\parskip0pt\parsep0pt
\item
  \texttt{X} {[} tseries {]} - Percentage rate of change in the input
  data.
\end{itemize}

\paragraph{Options}

\begin{itemize}
\itemsep1pt\parskip0pt\parsep0pt
\item
  \texttt{'outputFreq='} {[} \texttt{1} \textbar{} \texttt{2} \textbar{}
  \texttt{4} \textbar{} \texttt{6} \textbar{} \texttt{12} \textbar{}
  \emph{empty} {]} - Convert the rate of change to the requested date
  frequency; empty means plain rate of change with no conversion.
\end{itemize}

\paragraph{Description}

\paragraph{Example}

In this example, \texttt{x} is a monthly time series. The following
command computes the annualised rate of change between month t and t-1:

\begin{verbatim}
pct(x,-1,'outputfreq=',1)
\end{verbatim}

while the following line computes the annualised rate of change between
month t and t-3:

\begin{verbatim}
pct(x,-3,'outputFreq=',1)
\end{verbatim}


