Prague employs almost a fifth of the entire Czech workforce, and its wages are significantly above average (~+25%). In December 2015, average salaries available in Prague reached 35,853 CZK, an annual increase of 3.4%, which was nevertheless lower than national increase of 3.9% both in nominal and real terms. (Inflation in Prague was 0.5% in December, compared with 0.1% nationally.) Since 1990, the citys economic structure has shifted from industrial to service-oriented. Industry is present in sectors such as pharmaceuticals, printing, food processing, manufacture of transport equipment, computer technology and electrical engineering. In the service sector, financial and commercial services, trade, restaurants, hospitality and public administration are the most significant. Service (economics) account for around 80 percent of employment. There are 800,000 employees in Prague, including 120,000 commuters. The number of (legally registered) foreign residents in Prague has been increasing in spite of the countrys economic downturn. As of March 2010, 148,035 foreign workers were reported to be living in the city making up about 18 percent of the workforce, up from 131,132 in 2008. Approximately one-fifth of all investment in the Czech Republic takes place in the city.
Question: How many percentage points higher was the national annual salary increase compared to Prague?
Answer: .5