Complex sentence: The turnout compared to the 2001 election had risen by 7.4% to 41.5% (an above average increase), however this is still the lowest throughout the United Kingdom which averaged 61.3% with a 1.2% increase.
Split into simpler sentences: The turnout compared to the 2001 election had risen by 7.4% to 41.5% (an above average increase). However, this was still the lowest throughout the United Kingdom which averaged 61.3% with a 1.2% increase.