How do I get percentage changes instead of absolute levels in my R data download?

To change absolute levels to percentage changes, use this call:

data <- Quandl("NSE/OIL", transform="rdiff") 
Other transformations available include raw changes, normalized growth from 100 and cumulative sums:
data <- Quandl("NSE/OIL") 				# raw data
data <- Quandl("NSE/OIL", transform="diff") 	 	# changes
data <- Quandl("NSE/OIL", transform="rdiff") 		# percentage changes	
data <- Quandl("NSE/OIL", transform="normalize") 	# growth from 100
data <- Quandl("NSE/OIL", transform="cumulative") 	# cumulative sum