Without access to Booking.com's specific data, it's challenging to provide an exact figure, but I can make an informed estimate based on industry standards and various factors that impact booking cancellations. Globally, travel plans can be influenced by numerous elements such as socio-political shifts, economic recessions, health crises like pandemics, and changes in visa policies, among others. Moreover, Booking.com functions in various sectors—flights, hotels, rental cars, etc.—each exhibiting different cancellation rates. For example, hotel cancellations may occur more frequently, while flight cancellations are generally less common due to steeper penalties. Additionally, cancellation rates may fluctuate with the seasons. Considering these aspects, I would estimate that the global cancellation rate could be around 25%, but this is merely a conjecture, and the actual figure could vary based on the many factors mentioned.