Problem with List and HashMap [closed]

I have a list as stated below:

List<Map<String, String>> lista = new ArrayList<Map<String, String>>();

Map as stated below:

Map<String, String> mapa = new HashMap<String, String>();

Values are loaded in a for with results of a webservice as below:

if (propInfo1.getName().toString().equals("competencia")) {
    SoapObject obj2 = (SoapObject) obj1.getProperty(ret1);
    for (int ret2 = 0; ret2 < obj2.getPropertyCount(); ret2++) {
        PropertyInfo propInfo2 = new PropertyInfo();
        obj2.getPropertyInfo(ret2, propInfo2);
        competencia = new Competencia();
        if (propInfo2.getName().toString().equals("codCal")) {
            mapa.put("codcal", obj2.getProperty(ret2).toString());
        }
        if (propInfo2.getName().toString().equals("perRef")) {
            Object objData = (Object) obj2.getProperty(ret2).toString();
            try {
                Date date = DataUtils.stringToDate(objData.toString());
                mapa.put("perref", DataUtils.dataMesAno(date));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        if (propInfo2.getName().toString().equals("tipCal")) {
            mapa.put("tipcal", obj2.getProperty(ret2).toString());
        }
    }
    Log.i("Valor do Mapa", mapa.toString());
    lista.add(mapa);
    Log.i("Valor da Lista", lista.toString());
}

But values are being loaded duplicates

18704-18704/br.com.fjsa16.holerite I/Valor do Mapa﹕ {tipcal=Cálculo Mensal, perref=Abril / 2015, codcal=405}
18704-18704/br.com.fjsa16.holerite I/Valor da Lista﹕ [{tipcal=Cálculo Mensal, perref=Abril / 2015, codcal=405}]
18704-18704/br.com.fjsa16.holerite I/Valor do Mapa﹕ {tipcal=Cálculo Mensal, perref=Março / 2015, codcal=401}
18704-18704/br.com.fjsa16.holerite I/Valor da Lista﹕ [{tipcal=Cálculo Mensal, perref=Março / 2015, codcal=401}, {tipcal=Cálculo Mensal, perref=Março / 2015, codcal=401}]

In the logcat the map is loaded correctly but when added to the list it is loaded in duplicate form, ie the values are the same.

Has anyone ever come across this? Can you help me?