My family of 5 uses 100 to 125 gallons a day on average, based on my water bill. I'd guess our largest use is showers. I should note that we have low flow everything and high efficiency appliances, plus no sprinklers.
If all your fixtures are equally recent, it's likely that the toilet is the biggest use. But it might also be the most difficult one to reduce. In any case your per-capita consumption is already exemplary. Here in California the most extreme conservation measure they have managed to think up is households using more than 1000 gallons per day will be charged slightly more at the margins. I always look at these conservation proposals, then I look at my own bill, and I figure there's nothing I personally need to do.
Right, short of going without there isn't much more we can do.
In Hong Kong, 80% of homes flush with seawater [0]. It's provided for free by the government to encourage people to connect to that supply rather than the drinking water supply. I'm sure this can be done elsewhere.