\HeaderA{co2}{Mauna Loa Atmospheric CO2 Concentration}{co2}
\keyword{datasets}{co2}
\begin{Description}\relax
Atmospheric concentrations of CO\eqn{_2}{2} are expressed in parts per
million (ppm) and reported in the preliminary 1997 SIO manometric mole
fraction scale.
\end{Description}
\begin{Usage}
\begin{verbatim}co2\end{verbatim}
\end{Usage}
\begin{Format}\relax
A time series of 468 observations; monthly from 1959 to 1997.
\end{Format}
\begin{Details}\relax
The values for February, March and April of 1964 were missing and have
been obtained by interpolating linearly between the values for January
and May of 1964.
\end{Details}
\begin{Source}\relax
Keeling, C. D. and  Whorf, T. P.,
Scripps Institution of Oceanography (SIO),
University of California,
La Jolla, California USA 92093-0220.

\url{ftp://cdiac.esd.ornl.gov/pub/maunaloa-co2/maunaloa.co2}.
\end{Source}
\begin{References}\relax
Cleveland, W. S. (1993)
\emph{Visualizing Data}.
New Jersey: Summit Press.
\end{References}
\begin{Examples}
\begin{ExampleCode}
plot(co2, ylab = expression("Atmospheric concentration of CO"[2]),
     las = 1)
title(main = "co2 data set")
\end{ExampleCode}
\end{Examples}