In recent decades Sweden has become a more culturally diverse nation due to significant immigration; in 2013 it was estimated that 15 per cent of the population was foreign-born, and an additional 5 per cent of the population were born to two immigrant parents. The influx of immigrants has brought new social challenges. Violent incidents have periodically occurred including the 2013 Stockholm riots which broke out following the police shooting of an elderly Portuguese immigrant. In response to these violent events, the anti-immigration opposition party, the Sweden Democrats, promoted their anti-immigration policies, while the left-wing opposition blamed growing inequality caused by the centre-right government's socioeconomic policies.