Tesla is now providing sales numbers right after quarters end, so we don't have to wait for the quarterly conference calls anymore to find out how many EVs have been delivered in the part 3-month period. The latest numbers, for the April to June quarter, show that 11,507 Model S were delivered worldwide, a new record for the company. This is an impressive 52% increase over the same quarter in 2014, and this is without a new vehicle for sale. When the Model X comes out later this year (if all goes well, but Elon Musk has confirmed recently that thing are on track this time).
This brings the first half of the year to 21,537 vehicles delivered for Tesla so far in 2015.
So if the company is to hit the target of 55,000 EVs sold set by Elon Musk for this year, they would need to sell over 33,000 more in the back half of the year. That would be hard at a constant run rate, but Tesla has been increasing its production from quarter to quarter, so Q1 is usually the slowest quarter of the year, and each successive quarter gets better.
That's still a challenge, but Model X might come to the rescue in the last quarter, as there is pent up demand for it, so if production can keep up, it should be a big quarter.
Another thing that might help is the new all-wheel-drive 70D, which replaces the 60kWh entry level model, making it more attractive to people who were on the fence.