In the following paragraph, simple past has been used, rather than present perfect. I fail to understand why present perfect was not used. When we say 'over the past decade', it means the time extends upto present, but still present perfect was not used and I have seen many examples of present perfect being used on the internet with 'over the last' decade.
Over the past decade, India witnessed widespread economic growth as well as faster and more widespread poverty reduction. However, some states did not benefit as much as others. The seven ‘low-income states’ (LIS) in particular — Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Odisha, Rajasthan and Uttar Pradesh — continue to lag behind the rest of the country.
Why has simple past been used instead of present perfect? In my opinion "present perfect" should be as Over the past decade extends to present. How would the use of present perfect be different than simple past?