World industrial production and world imports show an upward trend along time. In statistical terms, they are not only integrated of order one but also co-integrated. We will rather focus here on the degree of cyclical link, i.e. the co-movement. Therefore, it is necessary first to extract the trend in order to compare the deviation to trend. Several types of filters are available to extract the trend. We will use the preferred Christiano-Fitzegerald filter.