My problems with the EUCheMS survey of European chemists and chemical engineers

Looks like people are being paid all right in Switzerland?
From Salzer et al. Chem. Eur. J. 2015, 21, 9921.

I am busy today, but I wanted to make note of my befuddlement with the pan-European employment survey published in Chemistry: A European Journal in June. I have been meaning to write on it for a while, but finally untracked myself this morning on Reddit. There are some very interesting tidbits in the survey, including the suggestion that the unemployment of the respondents was 3%. I'm skeptical of that number, but I am far more skeptical of our ability to learn anything from this survey, because of the difficulty of getting good data out of such a disparate population of chemists.

Here's how EUCheMS (a pan-European professional society of chemists, it seems) talked about the structure of the survey:

...A total of 4440 chemists and chemical engineers responded to the first issue of the European Employment Survey. This report does not differentiate between chemists and chemical engineers, and their responses have been evaluated jointly... 

...For convenience, in this Editorial this joint group of chemists and chemical engineers will simply be referred to as “chemists”. A rigid procedure was developed and applied to purge the responses of irregular answers. 3830 responses remained after this process and these were evaluated further. Particular emphasis was placed on the employment situation of chemists who graduated within the last 15 years, and 2445 responses came from chemists fitting this criterion. All responses were stored in anonymous form... 

...The questionnaire had six general sections (Personal Education / Employment / Job Training / Salary), which provided fields for free text responses. Industry employees were asked special questions in an additional section. The participation of industry employees accounted for 47 % of the responses. This group covered manufacturing industry,non-manufacturing industry, self-employed chemists, and publishing houses.The age of the responders exhibits a distinct maximum around 30 years of age (Figure 1)....  

...The results of a cross evaluation might be dominated by the large share of responders from Italy (my note: ~1000 respondents) and the UK (my note: ~750 respondents) (cf. Figure 2) and several conclusions could be heavily biased. Accordingly, this called for an evaluation of individual countries together with the joint evaluation of all European responses.... 

...EuCheMS currently has approximately 160000 individual members organized in 42 national member societies and supporting member groups. Those societies who agreed to participate in the survey account for approximately 90% of EuCheMS membership.

My issues:

• It seems goofy to report the salaries of chemists and chemical engineers together (it would be in the US, anyway, dunno about Europe.) 
• We have no idea how well this survey reflects the actual makeup of European chemists. 
• We have no idea how well this survey reflects the makeup of European chemical societies. 
• There was no attempt to understand who did not answer the survey. What was the response rate?
• There was no description of the survey instrument. (Was it online or on paper?) 
• There was no explanation of responses removed from the survey or why, just that it was "rigid." 
• We know that they focused on people who graduated in the last 15 years, but that they have a respondent who is 87 years old (did they throw that person out?).

While I think the survey is interesting, I don't think anyone should draw any conclusions from it. Readers, your thoughts?