Current U2 iTunes estimates.
So the newest Taylor Swift single has been #1 on the iTunes chart all week and estimated by HitsDoubleDaily to sell almost 275,000 downloads this week, which is on average 39,000 per day, and 1,600 downloads per hour.
For the past 4 hours, TBT has averaged around ~21% of Taylor's sales according to Kworb, which is roughly 1344 sales total. From 4 to 7 hours presumably averaged ~12% of Taylor's sales which is 576 sales total. From 7 to 11 it was ~5% of Taylor's total sales, or 320 sales total. For hours 11 - 14, it was charting fairly low around ~2% of Taylor's total sales or 96 total sales.
If it stays relatively steady overnight and gains slightly tomorrow, say holding around 25% of Taylor's sales on average for the next 26 hours, we could possibly see 10,400 sales in that period.
Which would bring us to `~12,700 downloads total for for this current tracking week.