Meyers Singleton Scope

In the following program, it seems like the Registry Singleton isn't being persisted across calls to the static functions. What is the problem with this approach?

#include <iostream>
#include <string>
#include <unordered_map>

using namespace std;

class Test {
typedef unordered_map<string,string> Registry;
public:
    static Registry &registry() {
        static Registry reg;
        return reg;
    }

    static void put(string key, string val) {
        Registry reg = Test::registry();
        reg[key] = val;
    }

    static string get(string key) {
        Registry reg = Test::registry();
        return reg[key];
    }
};

int main() {
    Test::put("a", "apple");
    Test::put("b", "banana");
    cout << Test::get("a") << endl;
    cout << Test::get("b") << endl;
    return 0;
}