require(quantmod) y <- getFX('USD/JPY', from=Sys.Date()-499, auto.assign=F) x <- index(y) y.above <- y[as.vector(y) > mean(as.vector(y))] y.below <- y[as.vector(y) < mean(as.vector(y))] x.above <- x[as.vector(y) > mean(as.vector(y))] x.below <- x[as.vector(y) < mean(as.vector(y))] class(y.above) class(y.below) plot(y, type='n', main='US Dollar vs. Japanese Yen') print(paste(length(x.below), length(y.below), sep=';')) polygon(x.below,y.below, col='green') polygon(x.above,y.above, col='red')