Complex sentence: According to a report released by the OECD in 2004, Luxembourg has the lowest total expenditure on health a share of GDP; likely attributed to Luxembourg's low population in comparison to the other countries.
Split into simpler sentences: According to a report released by the OECD in 2004, Luxembourg has the lowest total expenditure on health a share of GDP. This is attributed to Luxembourg's low population in comparison to the other countries.