yes you're correct.
I read it as 'roughly' the latter, so roughly Spring 2018 to Spring 2017, however, there's an implication that it's referencing the statistic instead of making a statement as the information is made available, hence "were" instead of a definitive "have". They haven't mentioned specific dates, so it could be a statistic that was true a week ago, or even up to a month ago. The statistic could only become available by the analyst every year during March. Hence the use of 'more than..' which implies that the information was found sometime in the near past and may now be an even higher count.
Saying, "over the past year" is easier to say than, "Working on numbers the analyst submitted in March".
Consider:
I paid all my taxes over the past year. All my receipts were in order.
Would be the same, however if the tax deadline was in March, and this was made known somehow in the context of the conversation, and it was now April, it could be disregarding any April payment.
Hope this helps?