how do i save stats?

script



game.Players.PlayerAdded:connect(function(plr)
    local stats = Instance.new('IntValue', plr)
    stats.Name = 'leaderstats'

    local experience = Instance.new('IntValue', stats)
    experience.Name = 'EXP'
    experience.Value = 0

    local level = Instance.new('IntValue', stats)
    level.Name = 'level'
    level.Value = 0

    experience.Changed:connect(function()
       level.Value = math.floor(experience.Value / 10)      


    spawn(function()
        while true do
            wait(3)
            experience.Value = experience.Value +1
        end
    end)
    end)
end)

how do i make a script so that it saves my script? with that i mean so if a player plays the game and leaves his experience value wil be saved.