I have a list of 1601 pairs of data (first is frequency in MHz, the second a phase error in degrees)

{{50.`, 0.21774563818642534`}, {54.34375`, 
  0.5304496217442711`}, {58.6875`, 0.5617827847178187`}, {63.03125`, 
  0.3362751440490217`}, {67.375`, 0.36882671665883704`}, {71.71875`, 
  0.4179775194472266`}, {76.0625`, 0.4506475692931553`}, {80.40625`, 
  0.44205688305458546`}, {84.75`, 0.4239454775684832`}, {89.09375`, 
  0.5143533696508089`}, {93.4375`, 0.41519057609652066`}, {97.78125`, 
  0.46836711367956685`}, {102.125`, 0.4502529991528945`}, {106.46875`,
   0.3330082492484374`}, {110.8125`, 
  0.43159288067712076`}, {115.15625`, 0.3956569101288583`}, {119.5`, 
  0.3787603542725497`}, {123.84375`, 
  0.24663322975607915`}, {128.1875`, 
  0.3767055532063148`}, {132.53125`, 0.4010673412291048`}, {136.875`, 
  0.5575086104092817`}, {141.21875`, 0.2823093773106544`}, {145.5625`,
   0.25466965847600864`}, {149.90625`, 0.4643294704271046`}, {154.25`,
   0.32120882966468134`}, {158.59375`, 
  0.401957752668447`}, {162.9375`, 0.27812625589707984`}, {167.28125`,
   0.2817343557882319`}, {171.625`, 0.1825520}}

I want to obtain the start at the 4th element, then drop every 9, so I get the 4th, 14th, 24th,34th etc element.

Any suggestions how to do this?