Of course it isn't as cut'n'dried easy at that, as each country has different demands on that reserve (debt servicing, capital outflows, pressures on its currency that depend on copper (Chile) or soya (Argentina) or ten thousand other variables). But the chart does give a general idea of strength.
The strongest country by far is Chile; this because as well as the $26.49Bn in official reserves used in the chart, it also has around $23Bn tucked away in overseas accounts to call on...add these together and Chile enjoys the backup of over $3,000 per capita. Next comes the quiet achiever Uruguay, once again showing itself in excellent position for the turbulence to come. Argentina and Venezuela are relatively rich at the moment, but both of those are more likely to tap reserves heavily in the near future.
Surprises include Bolivia, as the Evo Morales gov't has been fiscally prudent over the last two years (but don't spread that around...we don't need no stupid facts, right?). Also surprising but for the wrong reasons is the relatively low level of reserves that Colombia can call upon.
In general, the question to ask here is "Is $1,000 per head enough to protect a country?". That's one of those subjective, piece-of-string questions I suppose. But it does give us an idea of the numbers involved.