At the high point of her popularity during this term, 75 percent of Germans said they were satisfied or very satisfied with the job Merkel was doing, the map released by Statista on Friday shows.
But that was back in April 2014, long before Merkel said "wir schaffen das" (we can do it), thus announcing Germany's decision to take in large numbers of refugees from war-torn Syria.
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Before that statement at the end of August 2015, the Chancellor's approval rate had never dropped below 66 percent.
Since then it has never risen above 60 percent, sinking to a low of 45 percent in September after a summer of terror attacks and electoral humiliations at the hands of the far-right Alternative for Germany (AfD).
A recent survey showed Merkel is so unloved at the moment that Germans would pay more to go for a beer with football coach Jürgen Klopp than they would to go for dinner with their leader.
While the average respondent to a survey by online shopping deals website Shoop.de said they would pay €58,434 to have a pint with the passionate Liverpool FC boss, the average offered for a meal with Mutti was only €28,324.
But none of this put Merkel off deciding to run for a fourth term in next autumn's national election, an announcement she made on Sunday.
Maybe the general public have just been playing hard to get though, as new polling shows that a healthy majority have welcomed her decision to try and equal Helmut Kohl's record of 16 years as Germany's longest-serving Chancellor.
The poll published by broadcaster ZDF showed that 66 percent of the public were in favour of her running again, a number which rose to 89 percent of voters for her conservative Christian Democratic Union (CDU).
The announcement also gave a boost to the popularity of the CDU, which would win 36 percent of the vote if Bundestag elections were held on Sunday. In October the CDU sat at 33 percent.
Closest rivals the Social Democrats (SPD) dropped a percentage point to 21 percent in the poll.