Gtd is 7.8 
And a GTI is 6.5.
Now look at those numbers...... its playschool stuff Steve, just keep looking, and keep looking and keep looking. The hint is that the lower number means its faster. I'll go over that one more time. Look at the numbers, even write them down in biiiiiig digits and remember lower is better.
GTD = 7.8
GTI = 6.5
Can you spot the glaring difference yet ?