I would reword the whole thing and use the past tense because the pie chart reports statistics that were accurate when they were recorded.
As mentioned previously, half of the visitors stated that the trip was for pleasure.
Notice that the term trip is in the singular, so the auxiliary is singular too.
As trips are often categorized as being for pleasure or business, I chose to say pleasure instead of "vacation". In fact, the expressions business trip and pleasure trip are idiomatic in English.
If the statistic hovers around 50%, e.g., 48.9%, 51.2% then use an adverb such as: approximately, nearly, almost, close to or just under/over half
Approximately 50 percent of all visitors stated that their trip to (NAME OF COUNTRY) was for a vacation.
Examples found on Google Books
- Approximately half the visitors (53%) had season tickets and just under half (47%) were male
Festival and Events Management
Notice that the plural verb agrees with the subject visitors
N.B the preposition "of" can be dropped from half of, as seen in this example taken from the Bentley University research survey.
- Ranking second as a pre-trip influence and representing over half the visitors (53%) reported they also used printed brochures,
maps and travel guides to help plan a visit.