Vicki would like to estimate the probability of tails coming up fewer than 2 times in 3 coin flips. To do this, she has a computer randomly select 0 or 1 three times, with 0 representing heads and 1 representing tails. The results of 15 trials are shown in the table.

What is Vicki's estimated probability, based on this simulation?

Enter your answer as a fraction, in simplified form, in the box.