countries=CountryData["G8"];
gdp=CountryData[#,{"GDP",2006}]&/@countries;gdpPerCapita=CountryData[#,{"GDPPerCapita",2006}]&/@countries;population=CountryData[#,{"Population",2006}]&/@countries;data=Transpose[{population,gdpPerCapita}];dollarForm[a_Real]:=Row[{"$",NumberForm[a,{10,2},NumberPadding->{"","0"}]}]
dollarForm[q_Quantity]:=dollarForm[QuantityMagnitude[q]]

SectorChart[data,SectorOrigin->{Automatic,15000},LabelingFunction->(Placed[#,Tooltip,Style[Column[{Row[{"GDP: ",dollarForm[First@#*Last@#]}],Row[{"Population: ",NumberForm[First@#,{10,2},NumberPadding->{"","0"}]}],Row[{"GDP Per Capita: ",dollarForm[First@#]}]},Alignment->{Left,Bottom},Frame->True],14,FontFamily->"Helvetica"]&]&),ChartStyle->2,ChartLabels->Placed[countries,"RadialCallout",Style[#,12,FontFamily->"Helvetica",Darker@Brown]&],PlotLabel->Style["Visualizing GDP for the G8 Countries",14,Bold,FontFamily->"Helvetica",Darker@Brown],PlotRange->All,ChartLegends->Placed[gdp,Right,Style[dollarForm[#],FontFamily->"Helvetica"]&]]