what is the earliest dated time are monthly time series two dimensional can we have two dimensional data in simple time series when a time series is one-dimensional what is the difference between two-dimensional and one-dimensional data? what is the difference between a simple time series and a two dimensional time series are simple time series one dimensional what is one dimensional data why is my time series two dimensional are simple time series two dimensional what time period is one dimensional which time is considered two dimensional is a simple time series one dimensional? what is two dimensional time is the time series one-dimensional or two-dimensional when was simple monthly time series what is one dimensional data is a time series one dimensional is the simple time period one dimensional what is two dimensional data is time series one dimensional?