Brazil and Mexico are doing things a little bit differently as I noted before. They are allocating big chunks of address from LACNIC that they distribute in their countries. THe result is a three layered buffer of addresses (IANA -> LACNIC -> BRAZIL/MEXICO), not fair but that is how it is.
Brazil recently allocated an additional 2 million addresses from LACNIC. This allocation was a little bit surprising as they allocated 2 million addresses as early as in May this year. I suspect that a wireless operator that is building the next generation wireless network (LTE) allocated a big chunk of their old address space, forcing them to allocate more space from LACNIC. (every iphone, blackberry or other smartphone typically have a public IPv4 address)
The allocation is not affecting the overall IANA depletion date as RIPE is expected to allocate the last block from IANA. Right now only allocations made in the RIPE region will have any effect on the IANA depletion date. RIPE has not allocated any large blocks in several weeks now.