There was an increase of 100 x 15/100 = <<100*15/100=15>>15 visitors in November.
So, the number of visitors in November was 100 + 15 = <<100+15=115>>115.
In December, the number of visitors was 115 + 15 = <<115+15=130>>130
Therefore, a total of 100 + 115 + 130 = <<100+115+130=345>>345 visitors listed in these three months.
#### 345