std::vector of

I am trying to create a small interface function and to send it to a JSON formatter class. The JSON works only with (unlimited) key-value pairs, but the value can be (only): string, int, bool

Now I have:

struct Data
{   
    std::vector<std::pair<std::string, int64_t>> intData;
    std::vector<std::pair<std::string, std::string>> strData;
    std::vector<std::pair<std::string, bool>> boolData;
};

void func(const Data& data);

But I don't really like it (3 almost similar structures in Data), perhaps there is a better C++ way.

Ideally for me is to have something (templated) cleaner and to work like:

// pseudocode, I know that it does not work

struct Data
{   // AnyType = string, int or bool
    std::vector<std::pair<std::string, AnyType>> data;
};

// or better
using Data = std::vector<std::pair<std::string, AnyType>> data;

Data data;
data.add("int value", 1);
data.add("string value", "str");
data.add("bool value", false);

func(data);

Thanks

LE: I am using C++11, cannot use another standard unfortunately.