diff --git a/service.go b/service.go
index 474e7d6..297d9fd 100644
--- a/service.go
+++ b/service.go
@@ -6,6 +6,8 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+
+	"github.com/antonholmquist/jason"
 )
 
 // Service represents constantly updating info about single service.
@@ -52,14 +54,31 @@ func (s *Service) Update(wg *sync.WaitGroup) {
 
 	// For all vars, fetch desired value from Json and push to it's own stack.
 	for name, stack := range s.values {
-		value, err := expvar.GetInt64(name.ToSlice()...)
+		value, err := expvar.GetValue(name.ToSlice()...)
 		if err != nil {
 			continue
 		}
-		stack.Push(int(value))
+		v := guessValue(value)
+		if v != nil {
+			stack.Push(v)
+		}
 	}
 }
 
+func guessValue(value *jason.Value) interface{} {
+	if v, err := value.Int64(); err == nil {
+		return v
+	} else if v, err := value.Float64(); err == nil {
+		return v
+	} else if v, err := value.Boolean(); err == nil {
+		return v
+	} else if v, err := value.String(); err == nil {
+		return v
+	}
+
+	return nil
+}
+
 // Addr returns fully qualified host:port pair for service.
 //
 // If host is not specified, 'localhost' is used.
@@ -96,23 +115,23 @@ func (s Service) Value(name VarName) string {
 	if !ok {
 		return "N/A"
 	}
-	if val.Front() == 0 {
+	if val.Front() == nil {
 		return "N/A"
 	}
 
-	return fmt.Sprintf("%d", val.Front())
+	return fmt.Sprintf("%v", val.Front())
 }
 
-// Values returns slice of ints with recent values of the given var,
-// to be used with sparkline.
+// Values returns slice of ints with recent
+// values of the given var, to be used with sparkline.
 func (s Service) Values(name VarName) []int {
 	if s.Err != nil {
 		return nil
 	}
-	val, ok := s.values[name]
+	stack, ok := s.values[name]
 	if !ok {
 		return nil
 	}
 
-	return val.Values
+	return stack.IntValues()
 }
diff --git a/stack.go b/stack.go
index a1e55a8..3d924fa 100644
--- a/stack.go
+++ b/stack.go
@@ -8,7 +8,7 @@ const DefaultSize = 1200
 
 // Stack is a limited FIFO for holding sparkline values.
 type Stack struct {
-	Values []int
+	Values []interface{}
 	Len    int
 }
 
@@ -20,13 +20,13 @@ func NewStack() *Stack {
 // NewStackWithSize inits new Stack with size limit.
 func NewStackWithSize(size int) *Stack {
 	return &Stack{
-		Values: make([]int, size),
+		Values: make([]interface{}, size),
 		Len:    size,
 	}
 }
 
 // Push inserts data to stack, preserving constant length.
-func (s *Stack) Push(val int) {
+func (s *Stack) Push(val interface{}) {
 	s.Values = append(s.Values, val)
 	if len(s.Values) > s.Len {
 		s.Values = s.Values[1:]
@@ -34,9 +34,33 @@ func (s *Stack) Push(val int) {
 }
 
 // Front returns front value.
-func (s *Stack) Front() int {
+func (s *Stack) Front() interface{} {
 	if len(s.Values) == 0 {
-		return 0
+		return nil
 	}
 	return s.Values[len(s.Values)-1]
 }
+
+// IntValues returns stack values explicitly casted to int.
+//
+// Main case is to use with termui.Sparklines.
+func (s *Stack) IntValues() []int {
+	ret := make([]int, s.Len)
+	for i, v := range s.Values {
+		n, ok := v.(int64)
+		if ok {
+			ret[i] = int(n)
+			continue
+		}
+
+		b, ok := v.(bool)
+		if ok {
+			if b {
+				ret[i] = 1
+			} else {
+				ret[i] = 0
+			}
+		}
+	}
+	return ret
+}
diff --git a/stack_test.go b/stack_test.go
index 4837ea9..092d8dc 100644
--- a/stack_test.go
+++ b/stack_test.go
@@ -21,7 +21,7 @@ func TestStack(t *testing.T) {
 		}
 	}
 
-	if s.Front() != 14 {
+	if s.Front().(int) != 14 {
 		t.Fatalf("Front returns wrong value: expecting %d, got %d", 14, s.Front())
 	}
 }
diff --git a/ui_termui.go b/ui_termui.go
index 2ff8602..43a20cc 100644
--- a/ui_termui.go
+++ b/ui_termui.go
@@ -104,12 +104,14 @@ func (t *TermUI) Update(data UIData) {
 	t.Title.Text = fmt.Sprintf("monitoring %d services, press q to quit", len(data.Services))
 	t.Status.Text = fmt.Sprintf("Last update: %v", data.LastTimestamp.Format("15:04:05 02/Jan/06"))
 
+	// List with service names
 	var services []string
 	for _, service := range data.Services {
 		services = append(services, service.StatusLine())
 	}
 	t.Services.Items = services
 
+	// Lists with values
 	for _, name := range data.Vars {
 		var lines []string
 		for _, service := range data.Services {
@@ -119,9 +121,10 @@ func (t *TermUI) Update(data UIData) {
 	}
 
 	// Sparklines
+	topVar := data.Vars[0]
 	for i, service := range data.Services {
 		t.MemSparkline.Lines[i].Title = service.Name
-		t.MemSparkline.Lines[i].Data = service.Values(data.Vars[0])
+		t.MemSparkline.Lines[i].Data = service.Values(topVar)
 	}
 
 	termui.Body.Width = termui.TermWidth()