
year<-2000
a<-"http://canisius.edu/~yany/data/ibmMonthly.csv" 
x<-read.csv(a) 
tail(x)
x2<-data.frame(as.Date(x$Date,"%Y-%y-%d"),x$Volume)
x2[,3]<-format(x2[,1],"%Y")
colnames(x2)<-c("date","volume","year")
head(x2,3)
x3<-subset(x2,x2$year==as.character(year))
dim(x3)
sum(as.numeric(x3$volume))/1e9




