Regarding to the results - with regard to the results,
An other perspective - Another
remain to be one of the highest since more than two decades - have remained one of the highest for the past two decades
remains to be double - you've used this twice- I'd just remove 'to be'
double as high as all other countries - double that of all other countries
holds the record having the highest unemployment rates since the last two decades until 2002- I'm not sure the pahrase 'holds the rcord' works- it's not something to be proud of- had the highest unemployment rates for the two decades up to 2002
in the 90th = 90s
in between the 15 European Union members - among the 15...
In some countries like Germany and Finland- comma, and add them after 'therefore' and 'thus'
remain to have - I don't like this remain + infinitive structure