# save a numeric vector containing 72 monthly observations
myvector = .1*(1:72)+sin((1:72)*pi/12) + 
  rnorm(72,mean=0,sd=.3)

# from Jan 2009 to Dec 2014 as a time series object
myts = ts(myvector, start=c(2009, 1), end=c(2014, 12), 
          frequency=12)
class(myts)
plot(myts,col="blue")

# subset the time series (June 2014 to December 2014)
myts2 <- window(myts, start=c(2010, 6), end=c(2014, 12))
class(myts2)
plot(myts2,col="blue")