Not the snake but urban development. I catch so many in town/city areas and I think we can truly say said it has become a town dweller. Numbers caught on a yearly basis is more or less the same and I catch a lot in the same area.
Some stats for the Last 3 years:
Town 2008 / 2009 / 2010 (up to date)
Krugersdorp 11/ 9/ 12
Magaliesburg/Rural 7/ 7/ 9
Roodepoort 6/ 3/ 1
Randfontein 16/ 14/ 13
Westonarea 5/ 3/ 1
Carletonville 3/ 9/ 5