Berlin - Stamps Prices Decreasing?

Hello,
I have some sets of Berlin 1948-1949 and I would like to collect the missing sets.
When I am checking in my catalogue Michel 2009-2010, I see some prices for these sets.
But when I am looking on ebay the text of some announces, I see that the sellers give other Michel prices ( lower than mine!)
So, I would like to have your help about the latest Michel prices for these sets ( because if the prices are going down, no point to stay concentrate on them; better to work on other countries)
The sets I would like to have the latest Michel price ( 2015-2016 or 2016-2017)are: ( For used / **)
Mi#1 to 20: I have in my Mi2010 : 3000/450EUR
Mi#21 to 34: I have in my Mi2010 : 1000/1700EUR
Mi#35 to 41: I have in my Mi2010 : 60/900 EUR

Thank you

As of 2016:

1-20 -- €2,400 / €360
21-34 -- €900 / €1,400
35-41 -- €320 / €750

Thank you
It is Michel, right?
For the 35-41, used, it is 320 EUR?? Can you check if it is not 32 EUR?

Yes, that's from Michel. And €320 is correct for the set. The two DM values alone catalog used for €120 and €80.

Thank you.

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