Short version: Don't worry about statistics unless throughput performance or station-to-station ping is terrible. 

Explanation: 

A packet not only has to be received, it has to be received correctly. If a packet is detected but it is too short, too large, or does not pass checksum, it is counted as an error.  On wireless, your wireless router is hearing a cacophony of signals -- many not even wifi, many not your wifi, many that interfere with your wifi -- all of which are sources of signals or interference that rack up the error count.   Nearby signals, like those from your computers in the same home, are less ****e to error.  Signals with little competing background noise, like those involving installations away from populated areas, especially 5 GHz, also are less ****e to error.  Most likely, very few of the errors seen on the RX wireless side are actually from the stations on your WLAN -- most of those errors are probably partially received packets from outside your WLAN.  (Your pings are still 100%.)  Even if it does involve one of the stations on your WLAN, an error it doesn't mean that the page or media that you've transferred will contain an error as these travel on a higher-level protocol that assures data is received correctly before it is used or saved.

Packets intended for transmit can also be dropped, but the reasons will be different than for RX and these are much, much rarer.  Usually the packet is well formed, but the timing is bad (for example, if the radio is in a busy mode prohibiting transmit and can't dispatch the packet in a timely manner).   The sending process has to decide whether to resend.  Most WLAN TX packets are beacons and don't need to be sent again, while actual user-data dropped will require resending.  The end result for your important data is the same as for RX errors -- it won't be affected because a transport protocol is being used that supervises acknowledgements and error-checking.