Yeah, sorry, no numbers... I was drawing on anecdotal experiences.
I've also been to Nazca and my impression was that though the tourist traffic was only a tiny fraction of Machu Picchu, the town couldn't handle much more of it. Even in off season the airport was booked to capacity and people had to wait hours for scheduled flights.
Another example (besides Machu Picchu) that comes to mind is Paracas (https://en.wikipedia.org/wiki/Paracas_National_Reserve). It's hardly a mainstream tourist attraction, but the degradation from the tourist industry was pretty apparent when I visited in 2009, despite being a protected area.
I've also been to Nazca and my impression was that though the tourist traffic was only a tiny fraction of Machu Picchu, the town couldn't handle much more of it. Even in off season the airport was booked to capacity and people had to wait hours for scheduled flights.
Another example (besides Machu Picchu) that comes to mind is Paracas (https://en.wikipedia.org/wiki/Paracas_National_Reserve). It's hardly a mainstream tourist attraction, but the degradation from the tourist industry was pretty apparent when I visited in 2009, despite being a protected area.