(ShareCast News) - ITV delivered a strong financial performance for the first half of the year, with an interim dividend up 36%, but the television broadcaster's audience share was the lowest for 15 years.Total external revenue rose 11% to £1.4bn thanks to 5% growth in net advertising revenue, a 27% rise in online, pay and interactive TV sales and a 23% increase from ITV Studios.Group earnings before interest, tax, depreciation and amortisation (EBITDA) rose 24% to £400m, with a 26% rise from broadcast and online and 18% from Studios.Adjusted profit before tax increased 25% to £391m and adjusted earnings per share of 7.7p were 26% ahead of the same period last year.Directors declared an interim dividend of 1.9p, up 36%.But chief executive Adam Crozier admitted that with the 'ITV Family' group of channels seeing their share of viewing fall 4% in the half, one of his main focuses for the remainder of the year was to improve this.He said improvements in viewing figures were expected in the second half thanks to exclusive rights for the Rugby World Cup, which is being held in England and Wales, as well as a strong slate of drama. While the rugby will strenghten Setpember and October, ITV enters the football season without Champions League on its sporting calendar, having lost rights to BT.However, Crozier hailed the increasingly geographically diverse revenues the company now enjoyed: "More than half of ITV Studios revenue now comes from outside the UK and we further reinforced our position as a leading international producer with the acquisition of Talpa Media."He said the outlook for the full year was unchanged, with ITV Family net advertising revenue expected to be up 6% for the 9 months to the end of September, around 8% in the third quarter as the company expects to outperform the market again over the calendar year.ITV Studios was said to be on track to deliver strong revenue growth over the full year, with good organic growth and acquisitions "coming through as planned".Looking ahead to 2016, Crozier noted that ITV has looked to build on its rugby momentum by securing the joint rights to Six Nations Rugby and will show the European Football Championships later in the year, with newly secured deals for Britain's Got Talent and US animated comedies Family Guy and American Dad.