Spain\'s power giant Iberdrola posted Wednesday a slump in sales in the third quarter of 2013, blaming weak demand for electricity and gas in the struggling economies of the eurozone. Revenue dropped 10.5 percent from the level a year earlier to 7.38 billion euros ($10.1 billion) in the three months to the end of September, the group said in a statement. For the first nine months of 2013 combined, revenue fell 4.0 percent from a year earlier to 24.2 billion euros. \"Iberdrola\'s results for the period must be seen within the framework of a complex operating environment characterised by a difficult macroeconomic situation on an international level which materialised in a weak demand in electricity and gas in the eurozone,\" it said. This, together with higher levies and new regulatory measures, lowered revenues, especially in Spain and Britain, it said. Iberdrola reported a net profit of 546.7 million euros in the three months to September 30, emerging from a year-earlier loss of six million euros. For the first nine months of the year combined, the group said net profit fell 3.0 percent to 2.27 billion euros. Adding to the grim news, the group said it would cut the value of its 2013 dividend to investors by 10 percent compared to the previous year. Investors reacted by sending Iberdrola\'s shares tumbling 2.0 percent to 4.49 euros in the first hour of trade on the Madrid stock exchange.