Why has country X only Y teams although they are ranked high?
To determine the participants in the Champions League and the UEFA Cup, the ranking for the previous season is used, because each country should know at the start of the season for how many places its clubs are competing. For example, for the 2006/07 season the country ranking of 2005 (which covers the five seasons including and ending with 2004/5) has been used to determine the number of places. So there is a time lag for a country that is rising in the rankings, before its high ranking is reflected in the number of teams participating. This of course works the other way too, if a country is falling in the rankings, it will be a year before you see the effects in terms of its clubs in the European club competitions.