The data are interesting and could be spun quite a number of ways. There were altogether 75 respondents out of God-and-TAUS-know-how-many-approached. I presume the latter figure was mentioned in the live presentation. About half of these actually provide such services to their clientele. Given all the talk about MT and "our" post-editing future, what fraction of business do you expect this activity to represent among the respondents? For 86% it was less than 10% of current revenue. I'm guessing much less. A mere 1.8% reported in the 26 to 50% range and none above that. Reality Check #1. The tsunami of MT hasn't hit the profession, nor do the waters appear to be retreating at the beaches. So don't head for the hills just yet. I assume that a certain company which MT'd and post-edited some fifty kazillion Wikipedia articles into Thai was among the respondents, and even that visionary firm didn't break 50% for MT-postedit revenues. So, people, there probably is other work out there in at least the near future.
Reality Check #2: The majority of respondents also reported little or no increase in such business in the past year. Most (75%) of the "post-editors" are in fact part of the regular stables of translators at these agencies, but I suspect these workhorses are those unable to digest better feed and make more than horseshit out of it. Or they are starving. Or a bit adventurously masochistic and can't find where they left the cuffs and leather whip.
If you want to surf the MT-postedit wavelet, do so by all means. It could be an interesting diversion, and as in with any path taken in life, I expect you'll meet some people, possibly even ones worth knowing. But if this isn't your sport, don't think you're doomed to starvation and oblivion.
I don't know how large the total market is for my German to English translation pair, much less for any other combination. An estimate of 100 million euros would be far too low based on a quick napkin calculation of how many translators it supports and what they probably earn on average. Some billions I expect. In any case, even in a relatively small "market" for a common language, a translator would need to capture only a miniscule fraction of the business to make a moderate to good living. I suspect that even our blogging overworked American translator serves somewhat less than 0.001% of the German to English market. The line between starvation and survival and between survival and prosperity is not drawn by the available volumes in the FIGES markets nor even really by the average rates charged in them. Nor by skill as a translator beyond a certain reasonable standard to be expected in a particular discipline.
If you want to earn "enough" as a freelance translator in major language pairs and avoid the ball-and-chain future of an MT posteditor, and you have sufficient linguistic and personal skills to avoid embarrassing yourself or anyone who recommends you, getting "there" is mostly a matter of organization, discipline, initiative and a good service attitude. My attitude is mostly bad, and I still do OK. And I strive to improve that attitude by shooting and skinning pigs instead of customers that may appear to share some of their characteristics. Find a way to get the message of fair service to those who need it and you'll have the freedom to worry about other things, like if the apple grafts in the garden will take. If you're clueless as to what to do, I can't help you. But I can offer you a link to 25 things translators should never do.