A running chart - How many minutes a week?

I've started putting some of my old garmin runs into a spreadsheet. I want to make some nice graphs. I'd quite like to see how my running has changed over the past four years.

So here is the first one. I should add the caveat that i've been using a mix of the iphone and the Garmin watch and it sometimes takes a long time (sometimes up to 1km) to find a signal. In other words, I am probably slightly faster than it looks on the graphs to come over the next few weeks. Still very slow though!

Also, I havent ever kept a paper running diary so there will be lots of times when I have used running machines instead of running outside. This first table shows how many minutes I've run per week since just before Christmas. I know that I have been on a treadmill four or so times on top of this (around new year), so the minutes for the first week should probably be a bit higher.