I've collated the answers to some of the questions:
* How often do you encounter encryption? The most common answer is 'often'. Germany does not collect this statistic. Czech Republic and Hungary: 'rarely', Latvia has both 'often' and 'almost always' in bold, UK 'almost always'.
* Online encryption: most common one is e-comms (everywhere but Italy), followed by TOR (everywhere but Hungary and Poland). Denmark, Finland, Germany and the UK reported encountering all types of encryption on the form.
* Offline encryption: it's not very clear what is an encrypted device (it includes computers) and what is an encrypting application (they give disk encryption tools as examples), but all countries except Poland selected devices and all countries except Italy selected applications
* It sounds like the accused can only be compelled to disclose passwords or keys in the UK, but Italian LE would also like that very much, despite having reported that 'the current national law allows sufficiently effective securing of e-evidence when encrypted'.
* In Croatia, Latvia and Poland they consider that the current national laws don't allow effective securing of encrypted evidence. The answer to this question is not available for Czech Republic and the UK.
A few other interesting things I've noticed:
Croatia: 'There is no practical experience' regarding 'intercepting/monitoring encrypted data flow'; 'Tools for decryption are used in less complex case [...]. Foreign companies’ services were not used so far.'
Czech Republic: 'Additional intentional encryption is quite rare in most cases although encrypted mobile phones are more and more popular among members of certain organized crime groups.'
Denmark: 'The main issue with trying to decrypt encrypted data is of a technical nature. Furthermore the equipment needed to break encryption is costly and the process itself takes a lot of time.'; 'In general terms, we can inform you that commercial software is among the tools used to decrypt data'; 'Decryption typically requires large hardware resources (processing power) as the encryption offered by service providers is very strong.'
Estonia: 'The main problem is that communication or data are encrypted and if key is not available, it is not possible to decrypt them.'
Finland: 'In case of full-disk encryption, which is rare, we have to either use brute force attacks, or try to obtain the credentials some other way'; 'We do not usually use private sector companies for decryption purposes, but of course a large part of the software/hardware used are commercial products'; 'Wireless criminal intelligence gathering can be challenging, because the LE sector has limited legal rights to gather for example WIFI data'; 'Sometimes insufficient computational capacity of our password-breaking platforms make the decrypting process too lengthy'; In general they talk about C&C servers for botnets quite a lot.
Germany: Regarding intercepted encrypted comms: 'In many cases, analysis of actual communication content is not feasible.', 'A regulation to prohibit or to weaken encryption for telecommunication and digital services has to be ruled out, in order to protect privacy and business secrets.'
Hungary: it sounds like they gave the form to the wrong dept? 'Our unit is not dealing with decryption, therefore we do not have any practical experience in this field.', 'Our unit is not dealing with such techniques.'
Italy: covered in the OP
Latvia: 'LV sees as clear added value of EC3’s encryption/decryption platform; LV also highly values the availability of the Europol Platform for Experts.';
Poland: mostly covered in the OP, I'll add 'The specialised computers (GPU clasters[sic]) which can decrypt encrypted e-evidences are very expensive.'
UK: It reads like a polished PR piece, at least relative to the others. Provides non-answers. It's probably worth taking a closer look. For example to 'Under your national law, is it possible to intercept/monitor encrypted data flow to obtain decrypted data for the purposes of criminal proceeding?' they responded with 'Section 17 of the Regulation of Investigatory Powers Act 2000 prevents intercepted material from being used as evidence in legal proceedings.', which doesn't actually answer the question.