Libgdx with Proguard apk size is bigger than without - libgdx

Question

When I want to use Proguard with libgdx then the apk size gets bigger than without. Without it has a size of 3.01MB but with it has over 5MB and the classes.dex is like 4MB. The app include Admob, Google Play Services(trough BaseGameUtils) and Universal TweenEngine. I use the following proguard file:
# To enable ProGuard in your project, edit project.properties
# to define the proguard.config property as described in that file.
#
# Add project specific ProGuard rules here.
# By default, the flags in this file are appended to flags specified
# in ${sdk.dir}/tools/proguard/proguard-android.txt
# You can edit the include path and order by changing the ProGuard
# include property in project.properties.
#
# For more details, see
# http://developer.android.com/guide/developing/tools/proguard.html
# Add any project specific keep options here:
-verbose
-dontwarn android.support.**
-dontwarn com.badlogic.gdx.backends.android.AndroidFragmentApplication
-dontwarn com.badlogic.gdx.utils.GdxBuild
-dontwarn com.badlogic.gdx.physics.box2d.utils.Box2DBuild
-dontwarn com.badlogic.gdx.jnigen.BuildTarget*
-keepclassmembers class com.badlogic.gdx.backends.android.AndroidInput* {
<init>(com.badlogic.gdx.Application, android.content.Context, java.lang.Object,
com.badlogic.gdx.backends.android.AndroidApplicationConfiguration);
}
-keepclassmembers class com.badlogic.gdx.physics.box2d.World {
boolean contactFilter(long, long);
void beginContact(long);
void endContact(long);
void preSolve(long, long);
void postSolve(long, long);
boolean reportFixture(long);
float reportRayFixture(long, float, float, float, float, float);
}
-keep class com.badlogic.** {*;}
-keep class * extends java.util.ListResourceBundle {
protected Object[][] getContents();
}
-keep public class com.google.android.gms.common.internal.safeparcel.SafeParcelable {
public static final *** NULL;
}
-keepnames #com.google.android.gms.common.annotation.KeepName class *
-keepclassmembernames class * {
#com.google.android.gms.common.annotation.KeepName *;
}
-keepnames class * implements android.os.Parcelable {
public static final ** CREATOR;
}