6

For each year, print the year and the total number of submissions during that year. 
Sort by year in ascending order.

For each country, print the country and the total number of teams from that country.
Sort by country in ascending order.

Let C(I) be the number of teams from institution I over all years.
Print C(I) and I for all institutions I such that C(I) >= 10.
Sort results by decreasing C(I).
Sort results with the same C(I) lexicographically according to I.

Print the average number of team members.
Round the result to 2 decimal places.
Note 1: This is just a single value aggregated over all years.
Note 2: Don't forget to first print the number of results (which is 1) and only then the correct average.

For each division (open, secondary) compute the average age of team members who specified their age (i.e., have age > 0).
Print division and the average age rounded to 1 decimal place.
Sort results by division (first is open, then secondary).
(Note: This is aggregated over all years.)

For each year and each task in that year: print the year, the task name (a single letter) and the number of co-authors of that task.
Sort by year, then by task.