1) Over time we are getting...
Over the time period.
Over the time of the study.
Over the time interval.
Over the time of the class.
THE, with a specified time, not in general way.
2)Perhaps you might consider to change "even more
dependent..." to ''more and more
dependent...". Of course, if you mean "cada vez mais", I think it´s advisable to do so.
"Even more" generally comes before some statement/something that you have just declared.
In march some more small feature will follow to polish our favorite game even more!
Regarding national accounts, the problem is possibly even more acute because there is limited availability of data both in quantity and quality.
More examples athttp://www.linguee.com.br/ingles-portug ... +more.html
Your "even more" didn´t come after an afirmation/declaration, but it´s in the middle, it makes part of it. So, I think "more and more" adds more emphasis in the case. But then, it´s me, my opinion here.