Complex sentence: Support for the Union has since declined slightly, in part due to the political inroads made by pro-independence Plaid Cymru, although support for the Union is consistently shown as being at between 85 and 90 per cent of the population.
Split into simpler sentences: Support for the Union has since declined somewhat, reflected in the political inroads made by pro-independence Plaid Cymru. In recent years, support for the Union is consistently shown as being at between 85 and 90 per cent of the population.