public String getPopulationDetails(Field field)
    {
        StringBuffer buffer = new StringBuffer();
        if(!countsValid) {
            generateCounts(field);
        }
        for(Class key : counters.keySet()) {
            Counter info = counters.get(key);
            buffer.append(info.getName());
            buffer.append(": ");
            buffer.append(info.getCount());
            buffer.append(' ');
        }
        return buffer.toString();
    }