## How to deseasonalize quarterly data? ##
df <- as.data.frame(rnorm(40, 0, 1))
library(lubridate); library(zoo)
row.names(df) <- as.yearqtr(seq(ymd('2000-01-01'), by = '1 quarter', length.out=(40)))
df
seriestobedeseasonalized <- ts(df[,1])