.Berlin had over 31,000 domain names expire yesterday adding to the previous day where over 36,000 domain names expired.
.Berlin about a year ago allowed free domain registrations for 2 days, which totaled somewhere between 70,000-75,000 domain names with two registrants picking up almost 70,000 domain names just between the two.
At the moment .Berlin is now down to 82,481 domain names and is heading towards a 50% renewal rate unless registrants start renewing a boat load of these expired domains before they delete
According to ntldstats.com, which still counts expired domains since they have not been removed from the zone file, .Berlin still has almost 153,000 domain names registered and is the 7th most registered new gTLD extension.
SourceI assume that most registries would be happy with a 10% renewal rate of free domain names but in the case of .Berlin they may not hit that percentage of renewals