  Using three independent directions we estimate that the fraction of type Ia
supernovae (SNe Ia) exploding inside planetary nebulae (PNe), termed SNIPs,is
at least ~20%. Our three directions are as follows. (i) Taking the variable
sodium absorption lines in some SN Ia to originate in a massive circumstellar
matter (CSM), as has been claimed recently, we use the results of Sternberg et
al. (2014) to imply that > ~20% of SN Ia occur inside a PN (or a PN
descendant), hence classify them as SNIPs. (ii) We next use results that show
that whenever there are hydrogen lines in SN Ia the hydrogen mass in the CSM is
large (> 1 M_Sun), hence the explosion is a SNIP. We make the simplest
assumption that the probability for explosion is constant in time for up to
about 10^5 yrs after the merger of the core with the white dwarf (WD) in the
frame of the core-degenerate scenario. This results with at least few x10 of
SNe Ia that may have a SNIP origin. (iii) We examine the X-ray morphologies of
13 well-resolved close-by SN remnants (SNRs) Ia and derive a crude upper limit,
according to which 10-30% of all SNRs Ia possess opposite ear-like features,
which we take as evidence of SNIP origin. Our results, together with several
other recent results, lead us to conclude that the two scenarios most
contributing to SNe Ia are the core degenerate and the double degenerate
scenarios. Together these two account for >95% of all SNe Ia.
