The sympathies of the German political parties CDU / CSU have been measured every month. The figure below illustrates observations of the proportion of eligible voters in Germany who would vote for the CSU / CDU if there had been an election at the time of the survey, for the period January 1971 to April 1982 (T = 136 observations)

Percent 56 54 52 50 48 46 44 42 40 1971 1973 1975 1977 1979 1981Y + BIt-1