Taiwanese here, I think Taiwan's data is inaccurate. Our mobile carriers have a "unlimited" plan, which you can actually use unlimited data. The price of the plan varies a lot, but my unlimited plan only costs 499TWD/m(16.9USD/m), and I use nearly 50GB per mounth. But I'd like to mention there is no such as unlimited texts here, only unlimited data. I think this is why SNS is preferred over SMS and iMessage.