df <- data.frame(Product = LETTERS[1:20],
             Jan19 = rnorm(20), Feb19 = rnorm(20), Mar19 = rnorm(20),
             Apr19 = rnorm(20), May19 = rnorm(20), May19 = rnorm(20),
             Jun19 = rnorm(20))
 names(df) <- sub("19", " 19", names(df))