international markets was flat. We had increases in the U.K., Canada and South Africa, a flat LatAm region, and decreases in AsiaPac and Continental Europe.
This lower level of organic growth impacted operating profit in the quarter, which decreased from a year ago, to $207 million from $224 million. Operating margin was 11.0% compared to 11.7% in Q2-16, and decreased 30 basis points for the first six months.
During Q2 we used $60 million to repurchase 2.5 million shares, while over the trailing 12 months we utilized approximately $305 million for share repurchases. Since instituting our return of capital programs in 2011, we have returned $3.3 billion to shareholders in dividends and share repurchases, as well as reduced our dilutive share count by 28%.
Despite the fact that our year is off to a slow start, we continue to target 3 - 4% organic growth, although at the low end of that range. And we remain committed to delivering 50 basis points of operating margin expansion, to 12.5% for the full year. We’ve just completed the mid-year update with our agency leadership teams, and the tone and substance of those business reviews say that these goals remain achievable.
Importantly, in light of the broader caution that’s impacting clients’ willingness to spend, our teams remain fully focused on achieving our targeted margin improvement for the year. As you’d expect, we have intensified our plans to bring expenses fully in line with revenue in the second half.
Given our increased investment under robust growth over the last seven years, it wasn’t possible to reduce expenses in time to keep up with the slowing we experienced during Q2. But our strong record of expanding margins over many years speaks to the strength of our cost disciplines and our ability to execute. We are confident that the second half will benefit from our heightened focus on our expense base.
On the top line, we do expect to see improvements going forward, with modestly stronger growth from the advertising discipline in the second half, particularly with our largest clients. Some digital work, which is project-based by nature, was also uncharacteristically soft in Q2. Our digital agencies are best-in-class, with track records of delivering on their commitments, and results there should pick up in our second half.
Growth at our PR agencies is also expected to improve. This is a group that has outgrown the industry very consistently, with high-single-digit top-line cumulative growth over the past three years, and along the way has redefined the PR discipline for the digital age. Our takeaway from our recent review is that their second quarter, while disappointing, was an anomaly. The second half should reflect a stronger pipeline in these project-based businesses.
Our media business has continued to perform very well, and, as I remarked earlier, McCann, our largest agency, also had solid Q2 growth.
The macro climate in the U.S. and the overall tone from clients is supportive of a stronger second half, despite challenges caused by the political uncertainty. As you know, geographically the U.S. represents over 60% of our revenue mix, and our mid-year update says it should perform better in H2.
Obviously, our growth in the U.S. and that of our peer group so far this year has led to larger questions being asked about our sector. Accordingly, it is worth repeating that our media agencies continue to demonstrate their strong value for clients. The importance of the media agency has been amplified, rather than lessened, by the many demands of a complex,