What does over the past 10 years means?
'Over the past ten years' means 'during the last ten years'. This is a general way to refer to a time period and is often used with a present perfect continuous/progressive tense.
Here is an example side-by-side:
Over the past ten years I <em>have been developing</em> a new teaching curriculum.
During the past ten years I <em>have been developing</em> a new teaching curriculum.