gráfico, aquí está mi código:

private func setChart(pieChartView: PieChartView, values: [Double]) {

    var dataEntries: [PieChartDataEntry] = []

    let dataPoints = ["Mar","Apr","May"]

    for i in 0..<dataPoints.count {
        let dataEntry = PieChartDataEntry(value: values[i], label: dataPoints[i])
        dataEntries.append(dataEntry)
    }

    let pieChartDataSet = PieChartDataSet(values: dataEntries, label: "")
    pieChartDataSet.colors = [UIColor(red: 47/255, green: 164/255, blue: 59/255, alpha: 1.0),UIColor(red: 17/255, green: 128/255, blue: 127/255, alpha: 1.0),UIColor.orange]
    let pieChartData = PieChartData(dataSet: pieChartDataSet)
    pieChartView.data = pieChartData
    pieChartView.centerText = "Amount Spent"
    pieChartView.chartDescription?.text = ""
    pieChartView.usePercentValuesEnabled = true
    pieChartView.legend.horizontalAlignment = .center

}

¿Cómo agregar "%" en los datos de PieChart? NSNumberFormatter () ya no está disponible

---------------SOLUCIÓN---------------

Publico esta solución para todos los que tienen el mismo problema. Lo obtuve de chart-ios githup:

private func setChart(pieChartView: PieChartView, values: [Double]) {

    var dataEntries = [ChartDataEntry]()

    let dataPoints = ["Mar","Apr","May"]

    for i in 0..<dataPoints.count {
        let dataEntry = PieChartDataEntry(value: values[i], label: dataPoints[i])
        dataEntries.append(dataEntry)
    }

    let pieChartDataSet = PieChartDataSet(values: dataEntries, label: "")
    let green = UIColor(red: 47/255, green: 164/255, blue: 59/255, alpha: 1.0)
    let blue = UIColor(red: 17/255, green: 128/255, blue: 127/255, alpha: 1.0)
    pieChartDataSet.colors = [green, blue, .orange]
    let pieChartData = PieChartData(dataSet: pieChartDataSet)
    let formatter = NumberFormatter()
    formatter.numberStyle = .percent
    formatter.maximumFractionDigits = 2
    formatter.multiplier = 1.0
    formatter.percentSymbol = "%"
    pieChartData.setValueFormatter(DefaultValueFormatter(formatter: formatter))
    pieChartView.data = pieChartData
    pieChartView.centerText = "Amount Spent"
    pieChartView.chartDescription?.text = ""
    pieChartView.usePercentValuesEnabled = true
    pieChartView.legend.horizontalAlignment = .center
    pieChartView.drawEntryLabelsEnabled = false
    pieChartView.holeRadiusPercent = 0.55
    pieChartView.highlightPerTapEnabled = false
    pieChartView.animate(yAxisDuration: 2.0, easingOption: .easeInBack)
}