The tumbling pattern of a bar is the main parameter characterising its dynamics. This bar pattern speed, the bar ellipticity and its length are the three observational parameters that fully characterize bars. From numerical simulations, their evolution since bar formation is tightly linked to the dark halo in which the bar is formed through dynamical friction and angular momentum exchange. Observational measurements of the bar size and pattern speed with redshift can restrict models of galaxy formation and bar evolution. I shall present some recently published and new results of an observational study characterising the bar pattern speed and bar size evolution over the last 7 Gyr. We obtain the bar parameters using SDSS and COSMOS data. I will also present and discuss new results on the dependence of the bar pattern speed with Hubble type for nearby galaxies using the CALIFA data set and numerical simulations, and their impact on the bar parameter evolution.