| query | count | % | cumulative | comments |
| base system, total | 6803 | | | |
| base system, less than one year | 739 | 10.9 | 10.9 | |
| base system, 1-2 years old | 787 | 11.6 | 11.6 | |
| base system, 2-3 years old | 579 | 8.5 | 20.1 | |
| base system, 3-4 years old | 575 | 8.5 | 28.6 | |
| base system, 4-5 years old | 516 | 7.6 | 36.2 | |
| base system, 5-6 years old | 487 | 7.2 | 43.4 | |
| base system, 6-7 years old | 400 | 5.9 | 49.3 | |
| base system, 7-8 years old | 438 | 6.4 | 55.7 | past the 50% point |
| base system, 8-9 years old | 461 | 6.8 | 62.5 | |
| base system, 9-10 years old | 438 | 6.4 | 68.9 | |
| base system, 10-11 years old | 377 | 5.6 | 74.5 | |
| base system, 11-12 years old | 259 | 3.8 | 78.3 | |
| base system, 12-13 years old | 251 | 3.7 | 82.0 | |
| base system, 13-14 years old | 117 | 1.7 | 83.7 | |
| base system, 14-15 years old | 143 | 2.1 | 85.8 | |