And this ratio is heavily influenced by oil exports from Trinidad and Tobago to the rest of the region; if these are excluded (and who knows what Petro-Caribe will imply), the ratio is more in the region of 3 to 5 percent.
There is no chain reaction taking place. The reason they pop can be found in the design of the popcorn kernel. The kernel is protected by a hard outer shell or hull. Within, water is enclosed. Under sufficiently high heat, the water turns into steam, 4/6  BIS central bankers' speeches  raising the pressure inside the kernel.