g<-read.table("PIB.txt", col.names=c("fecha","DP"), sep=";",dec=",")

g$fecha <- as.Date(g$fecha, format="%d/%m/%Y")

t<-g$fecha
st<-length(g$DP)

ft<-plot(t,g$DP,type="l",ylab="US GDP", xlab="Tiempo",main="Evolución Histórica PIB US") 

#polygon(c(1, 1:st, st), c(0, g$DP, 0), col = "blue")

grid()

abline(h = 0, lwd = 1, col = "black")