effort vs months
months
  300 ++--------+---------+---------+---------+---------+---------+--------++
      +         +         +         +         +    A"data/em.sorted"   A    +
      |                                                                     |
  250 ++                                                                   ++
      |                                                                     |
      |                            A                                        |
  200 ++               A     A                                             ++
      |             AA   A                                   A              |
      |       AAA    A  A                                                   |
  150 ++        AA A  A  A                                                 ++
      |   AAAA A AA   A         A                                           |
      | AAAAA AA A A A  A  AA A A            A                      A       |
  100 ++AAAAAAAAAA AA A    A A  AA  A       A                              ++
      |AAAAAAAAAAAAAAAAAA AA                                                |
      AAAAAAAAAAAAAA AAA                                                    |
   50 AAAAAAAAAAAA                                                         ++
      AAAAA                                                                 |
      AA        +         +         +         +         +         +         +
    0 A+--------+---------+---------+---------+---------+---------+--------++
      0       20000     40000     60000     80000     100000    120000   140000
                                      effort