These reforms have been implemented through a wide range of measures that have substantially modified the pension system rules and parameters. One of the most important elements of pension reforms, aside of whether countries engaged or not in a systemic change, has been the introduction of mechanisms aimed at automatically adjusting (indexing) the key pension parameters (pension age, benefits, financing resources) to demographic pressure (e.g. changes in life expectancy, increase in the dependency ratio). Indeed, since the mid-1990's, half of the EU Member States have adopted either automatic balancing mechanisms, sustainability factors and/or automatic links between retirement age and life expectancy. All these pension reforms are projected to have a substantial impact on containing future pension expenditure trends. According to the latest long-term projections in the 2015 Ageing Report, public pension expenditure is projected to be close to 11% of GDP over the long run in the EU, almost the same as in 2013.