Comparison of the recent observation with the model extrapolation. Black dots show the position angle measurement as a function of time up to the year 2012. The orange pentagons show the 5 GHz data derived in this work. The black line shows the best-fit model to the data up to 2012 by Alberdi et al. (2013), excluding the new measurements, and extrapolated to the year 2021. The gray shaded region indicates the 1σ and 3σ contours.