If you are looking for the observed sunspot number derived from optical observations of the sun, you've been miss-routed.
This link provides a comparison of the effective SSN shown on this page to the observed solar sunspot number.

The effective sunspot number (SSNe) index is defined as that SSN which will return a zero average-error between foF2 values generated from a model (to which the SSNe is input) and a set of foF2 observations. The NWRA SSNe (solid lines on the plot) is generated by Northwest Research Associates, Inc., using mid-latitude foF2 observations from a single day as input (provided by the NOAA SWPC) and is based on the URSI-88 model.

The IPS T-index (dashed lines) is similar to the SSNe index in concept, although it is calculated using a different algorithm. The index plotted here is the daily value valid for the Australian sector calculated by the Australian IPS Radio and Space Services organization in Sydney, AU, as reported in their Daily Solar and Geophysical Report.

References for the SSNe and T indexes are as follows:

• Secan, J.A. and P.J. Wilkinson, Statistical studies of an effective sunspot number, Radio Science, 32, 1717-1724, 1997. [A comparison of various effective sunspot-number indices and discussion of the NWRA SSNe calculation.]
• Thompson, R. L., User requirements of aerospace propagation-environment modeling and forecasting, in Operational Modeling of the Aerospace Propagation Environment, AGARD-CP-238, edited by C. Soicher, 1978. [A brief discussion of an SSNe calculated by the USAF, no longer available outside the USAF.]
• Turner, J.F., The development of the ionospheric index T, IPS Series R Report, R11, June, 1968.
• Caruana, J., The IPS monthly T index, Solar-Terrestrial Predictions, Proceedings of a workshop at Leura, Australia October 16-20, 1989, Vol 2, pp 257-263, 1990.
• Wilkinson, P.J., Predictability of ionospheric variations for quiet and disturbed conditions, J. Atmosph. Terr. Phys., 57, 1469-1481, 1995.

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