“…The missing data are concentrated either at the beginning of the sample or in coincidence with war periods (for several European countries). For countries with missing data within the sample, such as Belgium, Germany, Spain, France, Netherlands, and Norway, co-integration analysis was performed using a wavelet-based approximation of the aggregate series, which yielded unbiased and consistent estimates for the intercept and slope parameters, as in Ramsey et al (2010), Gencay andGradejovic (2011), andRamsey (2012). In particular, wavelet multi-resolution decomposition analysis, by returning at each step a set of averages (along with a set of differences between adjacent averages) based on different window lengths, allowed us to obtain a collection of approximations of the original signal, from finer (S 1 ) to coarser (S 4 ) resolution levels.…”