Although incentives are declining in many European countries (some countries are even cutting their subsidies retroactively), the continent remains the largest solar energy market.
Mormons believe that families remain linked together eternally after death, and that one can even include ancestors into this union by retroactively baptising the dead.
Countries from Venezuela, Peru, Ecuador to Russia have shown that they can and do retroactively impose taxes on energy companies, or even outright expropriation.
For example, an employer must track exactly what percentage of full time a worker (even a salaried, professional one) puts in each year, and then retroactively adjust his partial pension accordingly.