That's normal I guess, there are fast charge (0% to xx%), slow charge (xx% to 99%), and trickle charge (the last 1%) for most phone nowadays, even feature phone. Trickle charge basically just quick charge-discharge cycle until it reach 100%, to protect the battery from overload, that's why it takes long time and not worth waiting for it for just 1%, just unplug your phone at 99% if you're in a hurry.