In the 21st century we have the largest, oldest and longest living population the world has ever known. In 2014, the world population totaled around 7,3 billion people. In developed countries, 20% of the population was aged 65 or above, with a life expectancy of around 80 years old. What is the cost of this expanding and ageing population? Well, developed countries now have health expenditures between 10% and 12% of their Gross Domestic Product. The greatest spender?