Complex sentence: Indeed, Greece has had some of the highest growth rates in Europe, averaging near 4% over the past several years, well above the EU average and is now considered by many to have reached the stage of a'mature' economy.
Split into simpler sentences: Indeed, Greece had some of the highest growth rates in Europe, averaging near 4% during this period, well above the EU average. It was considered by many to have reached the stage of a'mature' economy.