like swimming or I like swimming can be used to mean:
- I like to watch the sport of swimming.
- Swimming is my preferred option.
- Swimming is similar to some other activity
- I like to swim.
To explain #2: Maybe your co-worker says, "We have to organise an event, these are our options: football, swimming, paper airplane flying," and you reply, "I like swimming."
I like to swim can only mean something like
- I like to engage in the activity of propelling my body through a body of water.
Because "like swimming" can be used in several different ways, a simple word count like in that graph can't be used to support the proposition that "like swimming" is preferred over "like to swim" when used to mean the same thing.
Two of the four options I enummerate are hobbies (watching a sport and playing a sport are both hobbies) and they do take the gerund form "-ing" but "I like to swim" also refers to the hobby.
In answer to the plan-making question "What do you want to do tonight?", I don't think either "I like (to go) swimming" or "I like to swim" would be good answers. They don't (explicitly) address the question. Of course, there are people who would give such an indirect answer.
- Swim / Go swimming
- I would like to swim / to go swimming
- I want to swim / to go swimming
- Let's swim / Let's go swimming
would be appropriate as they do directly address the question. While the form "swim" (which I suppose is what you are using "do" to indicate) does appear in that list, "-ing" form is equally applicable. I don't know which is the more common when discussing plans but my naturally inclination would be either to answer "swim" or "go for a swim" or andy of the "swimming forms".
I would encourage you to avoid "wanna" and "gonna". They are not standard English.