Rome, November 14 - Italy's gross domestic product (GDP) rose 0.5% in the third quarter compared to the previous three months and was up 1.8% compared to the same period in 2016, according to calendar and seasonally adjusted estimates released by ISTAT on Tuesday. ISTAT said Tuesday that the "acquired" GDP rise for the 2017, what the annual increase will be if growth is flat for the rest of the year, is 1.5%. As a result the target of 1.5% growth for 2017 set out in the government's DEF economic blueprint has already be achieved. ISTAT's data released on Tuesday is seasonally and calendar adjusted, while the government's data is unadjusted. ISTAT's estimate that Italy's GDP rose by 1.8% in the third quarter with respect to the same period in 2016 means it is the biggest year-on-year increase since the second quarter of 2011. It also said GDP increase of 0.5% in the July-September period compared to the previous three months meant Italy has registered quarter-on-quarter growth for 13 consecutive trimesters. Growth was 0.3% in the second quarter.