Gradle takes a lot of minifying apk

I've been waiting for more than 20 minutes for Gradle to compile in the release, minifying and obfuscating the code with Proguard:

release {
    signingConfig signingConfigs.release
    shrinkResources true
    minifyEnabled true
    proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}

<============-> 93% EXECUTING [22m 37s]

Is it normal? How long does this process last?