So far for me 12 battles and nothing. Tower at 14.5%; that's 100/14.5 = 6.9 battles on average to get one relic drop.
I also know that the odds of getting a relic are 1 in 6.9 on every battle no change no matter how many battles are fought, however, there is also the Law of Averages.
If there is no problem with the stated percentage and the mathimatical equation that defines the relic drop, then the Law of Averages should begin to apply after a 500% to 1000% attempts. In other words, with a 14.5% ToR after 34 to 68 battles, you should have received at least one relic drop and the probability is that you could have expected at least 5 relics to drop.
Assumption:
Unfurtunately, the probabities apply on a World basis not on a player basis, therefore, the more players with ToR in their cities, the less likely of getting a relic. Some players will have better luck than others, but, on average across all players, the number of relic drops should reflect the Law of Averages as applied to the entire World, such as Arvahall, and to a single player over a vast number of battles.