Inflation is caused somehow by governments printing more and more money higher than the real GDP growth rates or faster than the real expansion of yearly production of goods and services produced . More money printed causes the real value of a unit currency including the US dollars to depreciate in terms of purchasing powers .
Countries make 100% sure price inflation happen by printing enought money and using it, but price inflation can happen without government help. NXT a 100% premined coin has inflation when compared with dollar despise no new coin being printed. Not only that, dollar already have price inflation because of previous said things at this post, so not the inflation is even bigger at NXT.